Skip to main content

Full text of "Turning and mechanical manipulation intended as a work of general reference and practical instruction on the lathe, and the various mechanical pursuits followed by amateurs"

See other formats 


TURNING 


AND 


MECHANICAL    MANIPULATION. 


BY   THE   LATE 

CHARLES    HOLTZAPFFEL, 

ASSOCIATE   OF   THE    INSTITUTION   OP    CIVIL   ENGINEERS,   LONDON  J 

HONORARY    MEMBER   OF   THE   ROYAL   SCOTTISH    SOCIETY    OF    ARTS,   EDINBURGH  J 

CORRESPONDING   MEMBER   OF    THE   AMERICAN    INSTITUTE   OF   NEW    YORK  J 

ALSO    OF   THE   AMERICAN   INSTITUTE,    PHILADELPHIA, 

ETC.,    ETC. 


a  2 


VOL.  1. 

MATERIALS ;  THEIR  DIFFERENCES,  CHOICE,  AND  PREPARATION  ;  VARIOUS  MODES 
OF  WORKING  THEM,  GENERALLY  WITHOUT  CUTTING  TOOLS. 


VOL.   II. 

THE   PRINCIPLES    OF   CONSTRUCTION,   ACTION,    AND   APPLICATION,    OF   CUTTING 

TOOLS  USED  BY  HAND ;  AND  ALSO  OF  MACHINES  DERIVED 

FROM  THE  HAND  TOOLS. 


VOL.   III. 

ABRASIVE  AND  MISCELLANEOUS  PROCESSES,  WHICH  CANNOT  BE 
ACCOMPLISHED  WITH  CUTTING  TOOLS. 


VOL.   IV. 
THE  PRINCIPLES  AND  PRACTICE  OF  HAND  OR  SIMPLE  TURNING. 

VOL.   V. 
THE  PRINCIPLES  AND   PRACTICE  OF  ORNAMENTAL  OR  COMPLEX  TURNING. 

VOL.   VI. 
THE  PRINCIPLES  AND    PRACTICE  OF   AMATEUR   MECHANICAL    ENGINEERING. 


TURNING 

AND 

MECHANICAL    MANIPULATION. 

INTENDED   AS 

WORK   OF   GENERAL   REFERENCE  AND    PRACTICAL   INSTRUCTION, 

ON  THE  LATHE, 

AND  THE  -VARIOUS  MECHANICAL  PURSUITS 
FOLLOWED  BY  AMATEURS- 


BY  THE  LATE 

CHARLES   HOLTZAPFFEL, 

ASSOCIATE   OF   THE   INSTITUTION   OF    CIVIL   ENGINEERS,   LONDON  ; 

HONORARY    MEMBER    OF    THE    ROYAL   SCOTTISH    SOCIETY    OF    ARTS,   EDINBURGH 

CORRESPONDING   MEMBER    OF    THE    AMERICAN    INSTITUTE    OF    NEW    YORK   ; 

ALSO    OF    THE    FRANKLIN    INSTITUTE,    PHILADELPHIA, 

ETC.,   ETC. 


TO  BE  COMPRISED  IN  SIX  VOLUMES. 


VOL.  III. 

ABRASIVE  AND  MISCELLANEOUS  PROCESSES,  WHICH  CANNOT  BE 
ACCOMPLISHED  WITH  CUTTING  TOOLS. 


Illustrated  by  upwards  of  One  Hundred  and  Eighty  Wood  Cuts.      . 

i     it    \ 


LONDON: 

RELISHED  EY  HOLTZAPFFEL  &  Co.,  64,  CHARING  CROSS,  AND 
127  LONG  ACRE. 

And  to  be  had  of  all  Booksellers. 
1850. 


LONDON  : 
BRADBURY   AND   EVANS,  PRINTERS,  WHITEPUIARS. 


PREFACE  TO  THE  THIRD  VOLUME. 

LN  offering  to  the  public  the  third  volume  of  the  late  Mr.  Charles 
HoltzapffeFs  work  on  Turning  and  Mechanical  Manipulation, 
some  explanation  is  required  of  the  circumstances  under  which 
the  work  has  been  continued.  On  the  premature  and  lamented 
death  of  the  highly  talented  author,  it  became  necessary  either 
to  abandon  the  work,  or  to  endeavour  to  realize  the  views  with 
which  it  had  been  undertaken.  In  deciding  on  the  latter 
course,  Holtzapffel  &  Co.  were  influenced  partly  by  the  circum- 
stance, mentioned  in  the  preface  to  the  first  volume,  of  the 
absence  of  any  general  treatise  in  the  English  language  for  the 
guidance  of  amateurs  of  mechanical  pursuits,  but  principally  by 
desire  of  fulfilling  the  intentions  of  the  author,  and  of  pre- 
iting  disappointment  to  his  kind  and  numerous  patrons,  who 
lave  most  strenuously  urged  the  importance  of  completing  the 
/ork,  more  especially  as  the  first  two  volumes  had  been  so 
ivourably  received  by  the  public. 

The  arrangement  of  the  subjects  to  be  treated  on  in  the 
>resent  and  succeeding  volumes  had  been  determined  on  by  the 
ite  author,  many  notes  had  been  written,  and  considerable 
jress  made  in  the  advancement  of  the  work.      The  third 
)lume  being  now  completed,  it  is  respectfully  submitted  to 
ie  public,  with  humble  confidence  that  it  will  be  received  with 
leniency. 


Vlll 


In  compiling  the  present  volume  every  endeavour  has  been 
made  to  follow,  as  closely  as  possible,  the  course  indicated  by 
the  late  Mr.  C.  Holtzapffel,  and  it  is  trusted  that  these  efforts 
have  been  in  great  measure  successful;  but  notwithstanding 
that  every  care  has  been  taken  to  render  this  part  of  the  work 
as  complete  and  correct  as  possible,  imperfections,  omissions, 
and  errors,  have  doubtless  arisen ;  it  is  hoped  that  these  defects 
will  be  viewed  with  liberal  kindness,  and  pointed  out  for  future 
correction. 

In  conclusion,  it  may  be  permitted  to  mention  that  the  delay 
in  the  completion  of  the  present  volume  has  been  considerably 
increased  by  the  interruptions  of  ordinary  business,  and  other 
circumstances  wholly  unavoidable.  It  is,  however,  fully  expected 
that  the  fourth  volume  will  be  published  within  a  much  more 
limited  period,  as  the  late  author's  notes  on  its  subjects  are 
more  complete,  and  upwards  of  one  hundred  and  fifty  pages  had 
been  printed  under  his  personal  superintendence. 


CHARING  CROSS,  LONDON, 
December  5,  1850. 


GENERAL  SKETCH 

OF   THE 

CONTENTS  OF  THE  .WORK. 


VOL.  I. 
[ATERIALS,   THEIR   DIFFERENCES,     CHOICE,    AND    PREPARATION;    VARIOUS 

MODES  OF  WORKING  THEM,  GENERALLY  WITHOUT  CUTTING  TOOLS, 
itroduction— Materials  from  the  Vegetable,  the  Animal,  and  the  Mineral  Kingdoms.— Their 
uses  in  the  Mechanical  Arts  depend  on  their  structural  differences,  and  physical  characters. 
The  modes  of  severally  preparing,  working,  and  joining  the  materials,  with  the  practical  descrip- 
tion of  a  variety  of  Processes,  which  do  not,  generally,  require  the  use  of  Tools  with  cutting  edges. 

VOL.  II. 

IE  PRINCIPLES  OF  CONSTRUCTION,  ACTION,  AND  APPLICATION,  OF  CUTTING 
TOOLS  USED  BY  HAND  ;  AND  ALSO  OF  MACHINES  DERIVED 

FROM  THE  HAND  TOOLS, 
le  principles  and  descriptions  of  Cutting  Tools  generally — namely,  Chisels  and  Planes,  Turning 
Tools,  Boring  Tools,  Screw-cutting  Tools,  Saws,  Files,  Shears,  and  Punches.     The  hand  tools 
and  their  modes  of  use  are  first  described  ;  and  subsequently  various  machines  in  which  the 
hand  processes  are  more  or  less  closely  followed. 

VOL.  III. 

ABRASIVE  AND  MISCELLANEOUS  PROCESSES,  WHICH  CANNOT  BE  ACCOM- 
PLISHED WITH  CUTTING  TOOLS. 

Grinding  and  Polishing,  viewed  as  extremes  of  the  same  process,  and  as  applied  both  to  the  pro- 
duction of  form,  and  the  embellishment  of  surface,  in  numerous  cases  to  which,  from  the 
nature  of  the  materials  operated  upon,  and  other  causes,  Cutting  Tools  are  altogether  inappli- 
cable. Preparation  and  Application  of  Varnishes,  Lackers,  &c. . 

VOL.  IV. 

THE  PRINCIPLES  AND  PRACTICE  OF  HAND  OR  SIMPLE  TURNING. 
Descriptions  of  various  Lathes ; — applications  of  numerous  Chucks,  or  apparatus  for  fixing  works 
in  the  Lathe.    Elementary  instructions  in  turning  the  soft  and  hard  woods,  ivory  and  metals  , 
and  also  in  Screw-cutting.    With  numerous  Practical  Examples,  some  plain  and  simple,  others 
difficult  and  complex,  to  show  how  much  may  be  done  with  hand  tools  alone. 

VOL.  V. 

PRINCIPLES   AND   PRACTICE  OF   ORNAMENTAL    OR   COMPLEX    TURNING. 
Sliding  Rest  with  Fixed  Tools— Revolving  Cutters,  used  in  the  Sliding  Rest  with  the  Division 
Plate  and  Overhead  Motion.    Various  kinds  of  Eccentric,  Oval,  Spherical,  Right-line  and  other 
Chucks.    Ibbetson's  Geometric  Chuck.    The  Rose  Engine,  and  analogous  contrivances,  &c. 
With  numerous  Practical  Examples. 

VOL.  VI. 

THE  PRINCIPLES  AND  PRACTICE  OF  AMATEUR  MECHANICAL  ENGINEERING. 
Lathes  with  Sliding  Rests  for  metal  turning,  Self-acting  and  Screw- cutting  Lathes— Drilling 
Machines — Planing  Engines — Key-groove,  Slotting  and  Paring  Machines — Wheel-cutting  and 
Shaping  Engines,  &c. 

With  numerous  Practical  Examples. 

%*  The  First,  Second,  and  Third  Volumes  of  this  worli,  are  written  as  accompanying 
books,  and  have  one  Index  in  common,  so  as  to  constitute  a  general  and  preliminary  work,  the 
addition  to  which  of  any  of  the  other  volumes,  will  render  the  subject  complete  for  the  three  classes 
of  Amateurs  referred  to  in  the  Introductory  Chapter. 

A  few  additional  copies  of  the  Index  have  been  printed  for  the  convenience  of  those  who  may 
desire  to  bind  the  Index  with  Vols.  I.  and  II. 


TABLE  OF  CONTENTS  OF  THE  TRIED  VOLUME. 


CHAP.  XXXI.— GENERAL  REMARKS  UPON  ABRASIVE  PROCESSES. 

PAGE 

INTRODUCTION — Comparison  of  abrasive  and  cutting  processes  .     1026 

1.  Preliminary  observations  on  grinding  and  polishing — First,  on  the 
substances  that  are  to  be  ground  and  polished  —  Secondly,  on  the 
materials,  or  abrasive  powders,  by  the  successive  employment  of 
which  different  substances  are  polished — Thirdly,  on  the  tools  or 
apparatus  by  the  agency  of  which  abrasive  substances  are  applied  to 
the  objects  to  be  ground  and  polished  .  .  .  1028 

SECT.  2.  Descriptive  Catalogue  of  the  apparatus,  materials,  and  processes,  for 
grinding  and  polishing,  commonly  employed  in  the  mechanical  and 
useful  arts — Including  bobs,  bouldering  stones,  brushes — buff  leather  ; 
polishers,  sticks,  and  wheels — burnishers  of  various  kinds — caps — 
cloth ;  polishers,  rubbers,  and  wheels — emery ;  cake,  cloth,  paper, 
powders,  sticks,  and  wheels  —  Fayrer's  swing  hone  —  glass  paper, 
glazers — leather;  polishers,  rubbers,  and  wheels — mills — moslings;  oil- 
stones— polishers  and  rubbers  of  various  forms  and  materials— rumble 
or  shaking  machine— skive — slicer — Wheels  of  natural  stone,  as  grind- 
stones ;  different  methods  of  mounting  these  ;  driven  by  manual  and 
steam  power;  hacking,  jarring,  roving,  straggling,  and  turning  grind- 
stones, to  keep  them  in  order.  General  methods  of  application  to 
works  of  large  and  small  size,  dry  and  wet  stones— Wheels,  of  factitious 
stone  or  composition  wheelsj  of  crocus,  corundum,  and  emery — Wheels 
of  metal,  or  metallic  laps,  constructions  and  applications  of  those  used 
by  cutlers,  diamond  polishers,  engineers,  glass-grinders,  lapidaries, 
and  mechanists  generally — Wheels  of  wood  or  glaze  wheels,  used  by 
cutlers,  glass-cutters,  and  lapidaries — Wheels  of  leather  or  buff 
wheels,  glazers  and  polishers;  general  construction,  action,  and  appli- 
cation, for  polishing  cutlery,  lapidary,  and  metal  works — Wheels  of 
cloth,  for  ivory-workers,  lapidaries,  &c. — Wheels  of  bristles  or  wire,  for 
curved,  chased,  and  pierced  works. 

Preparation  and  application  of  grinding  and  polishing  materials — 
chalk,  charcoal,  corundum,  diamond,  Dutch  rush,  emery,  fish-skin— 
Flanders  brick,  flint,  gannister  stone,  glass,  gritstones,  and  hone 
slates  of  various  kinds — lime,  loam,  oilstone,  oxides  of  iron,  lead,  and 
tin — pumice-stone,  putty-powder,  rottenstone,  sand,  sawdust,  Tripoli, 
and  whiting. 

General  methods  of  grinding  and  polishing — albata — brass;  cast, 
filed,  stamped,  and  turned  works — Britannia  and  bronze  metals- 
braziers'  and  coppersmiths'  works— cutlery  and  edge  tools;  best  and 


TABLE    OF    CONTENTS    OF    VOL.  III. 


ordinary — electrum,  enamels,  fluor-spar,  glass,  gold,  and  granite — 
horn,  ivory  and  bone  ;  carved,  flat  and  turned  works— Lapidary  works, 
general  routine  illustrated  by  the  three  different  modes  of  cutting, 
grinding,  and  polishing,  alabaster,  carnelian,  and  sapphire — lists  of 
materials  treated  in  a  similar  manner,  with  remarks  upon  the  pecu- 
liarities of  working  all  the  principal  substances  employed  by  the  , 
lapidary — Polishing  lithographic  stones— machinery,  large  and  small ; 
flat  and  turned  works,  in  iron  and  steel — marble  ;  flat,  ornamented, 
sculptured,  and  turned  works — marquetry  works  in  wood  and  metal 
—mineral  substances,  painted  works,  porphyry,  platinum,  and  scag- 
liola— shells,  nacreous  and  porcellaneous— carving  shell  cameos — 
Polishing  silversmiths'  works  —  slate,  tortoiseshell,  and  varnished 
works — whalebone — woods ;  hard  and  soft,  flat  and  turned — wrought- 
iron  and  zinc  ....  ...  1033 


CHAP.  XXXII.— GRINDING  AND  SHARPENING  CUTTING  TOOLS. 

SECT.  1 .  Grinding  cutting  tools  on  the  ordinary  grindstone — Importance  of  the 
grindstone — various  arrangements  of  frames  for  grindstones  driven 
by  handles  and  treadles — Grinding  and  polishing  lathe  for  amateurs 
— General  remarks  on  grinding  tools — Examples  :  grinding  carpen- 
ters' bench  plane-irons,  chisels,  gouges,  and  moulding  plane-irons ; 
turners'  chisels  and  gouges — flat,  side,  triangular,  and  square  tools — 
Gravers,  drills,  and  point  tools — Round  and  heel  tools — Slide  rest- 
tools  and  cutters  .  .  .  .  .1127 

SECT.  2.  Sharpening  cutting  tools  on  the  oilstone — General  remarks  on  oil- 
stones, and  angles  at  which  the  tools  are  held — Examples  :  carpen- 
ters' tools,  bench  plane-irons,  chisels,  gouges,  and  moulding  plane-irons 
—Turners'  chisels,  gouges,  flat,  moulding,  and  other  tools  for  wood, 
ivory,  and  brass  .  .  .  .1141 

SECT.  3.  Setting  razors — Proportions  and  sections  of  razors,  various  modes 
in  which  they  are  ground — Tests  for  keenness  of  edge — Faulty  con- 
ditions of  razors — Whetstones  usually  employed  —  Setting  edge  of 
razors — Razor  strops  .  .  .  .  .  .  .1146 

SECT.  4.  Sfiarpening  cutting  tools  with  artificial  grinders — Horizontal  grinding 
machine — Guides  for  grinding  tools  to  definite  angles — Instrument 
for  grinding  and  setting  ordinary  turning  tools — Instrument  for  setting 
rose-engine  tools — Instrument  for  sharpening  straight  and  angular  tools 
for  ornamental  turning — Vertical  lap,  mounted  on  lathe,  for  setting  tools 
— Sharpening  tools  with  concave  edges — Conical  grinders  for  bead  tools 
and  drills  —  Sharpening  ornamental  drills  and  cutters  —  Sharpening 
moulding  tools,  figured  punches,  &c.  —  Sir  J.  Robison's  instrument 
for  setting  the  edges  of  pen-knives,  razors,  and  surgical  instruments  .  1156 

CHAP.  XXXIII.— THE  FIGURATION  OF  MATERIALS  BY  ABRASION. 

SECT.  1 .  The  production  of  plane  surfaces  by  abrasion  —  General  remarks, 
principal  dependence  for  accuracy  of  form  placed  upon  that  of  the 
abrasive  tool,  or  on  the  relative  motions  of  the  grinder  and  work — 


TABLE  OF  CONTENTS  OF  VOL.  in. 

PAGE 

Revolving  laps  for  flat  works  in  metal — Lapping  flat  surfaces — Cut- 
ting facets  on  steel  jewellery,  facetting  gold  and  silver  works — Watch- 
makers' Geneva  tool  for  polishing  flat  heads  of  small  screws — 
Grinding  large  flat  works  in  metal— Nasmyth's  machine  for  flat  sur- 
faces— General  methods  pursued  in  the  figuration  of  materials  by 
abrasion  illustrated  by  the  modes  of  working  stone  and  marble — saws 
for  soft  stone  —  saws  for  hard  stone  and  marble  —  setting  out  and 
sawing  blocks  of  marble  and  slabs — grub-saws  for  narrow  slips  and 
small  works—  grinding  and  polishing  plane  and  figured  surfaces  by 
hand,  inlaid  works — Application  of  machinery  to  working  marble — 
machine  for  large  blocks — Tulloch's  sawing  machine  for  slabs — cir- 
cular sawing  machine  for  narrow  slips  —  sawing  circular  works — 
revolving  laps  for  grinding  plane  surfaces  —  grinding  machine  for 
large  slabs — machine  for  working  mouldings — polishing  machine — 
Manufacture  of  plate-glass — grinding  machines — smoothing  by  hand 
— polishing  machines — Manufacture  of  sheet-glass  —  grinding  and 
polishing  machines— Grinding  accurate  plane  surfaces,  illustrated  by 
methods  pursued  for  optical  purposes — grinding  parallel  disks  of  glass 
for  sextants — plane  specula  .  .  .  .  .  .1179 

SECT.  2.  The  production  of  cylindrical  surfaces  ly  abrasion — Grinding  external 
cylindrical  surfaces  in  metal — Clamps  used  by  hand,  or  in  the  lathe, 
for  rods,  lathe  mandrels,  gages,  rollers,  &c.  —  Fixed  and  revolving 
grinders,  mounted  in  the  lathe  for  accurate  works — Grinding  accurate 
cylindrical  rollers  for  paper-making  with  water  only — Grinding  cylin- 
drical rims  of  pulleys — Mr.  J.  Whitelaw's  and  Messrs.  Randolph  & 
Elliott's  machines — Grinding  internal  cylindrical  surfaces — Solid  and 
expanding  grinders  for  cylindrical  holes — Fitting  together  external 
and  internal  cylinders  .......  1232 

SECT.  3.  The  production  of  conical  surfaces  by  abrasion — Grinding  external 
conical  surfaces  in  metal ;  grinders  similar  to  these  employed  for 
cylinders — Clamps  for  short  cones,  lathe  mandrels,  &c. — Fixed  and 
revolving  grinders — Grinding  conical  holes — Solid  and  spring  grinders 
for  axletree-boxes,  collars  for  lathe  mandrels,  &c.  .  .  .  1252 

SECT.  4.  The  production  of  spherical  surfaces  by  abrasion —  Guy's  method  of 
grinding  accurate  spheres  in  hardened  steel,  glass,  &c.  ;  one  of  the 
most  unexceptionable  examples  of  the  production  of  form  by  abrasion 
—  Grinding  spherical  surfaces  for  lenses — formation  of  the  grinding 
tools— motions  given  to  the  tool,  correction  of  curvature— preparation 
of  the  glass — rough  and  smooth  grinding — Polishing  lenses — cloth 
polisher  for  lenses  of  ordinary  accuracy — grinding  the  edges  circular 
— Varley's  lathe  for  grinding  and  polishing  lenses  and  specula  — 
machinery  for  grinding  common  lenses — Grinding  and  polishing  best 
lenses  for  object  glasses — silk  polisher — accuracy  of  radius  of  curva- 
ture, Ross's  sphereometer — Grinding  and  polishing  lenses  for  micro- 
scopes—  Grinding  and  polishing  specula  for  reflecting  telescopes  — 
Small  specula  ground  and  polished  by  hand  —  rough  grinding  with 
emery,  smoothing  with  bed  of  hones,  polishing  tools — preparation  of 
pitch  polisher— manipulation  and  sources  of  error  in  the  hand  process 


TABLE    OF    CONTENTS    OF   VOL.  Ill, 

PAGE 

— The  Earl  of  Rosse's  machine  for  grinding  and  polishing  three-foot 
speculum  —  management  of  the  resinous  composition  for  the  polisher 
— modifications  adopted  in  grinding  and  polishing  the  six-foot  spe- 
culum— Methods  of  supporting  specula  in  telescopes,  and  while  being 
figured  —  Mr.  W.  Lassell's  machine  for  polishing  specula — Dr.  R. 
Greene's  machine  for  grinding  and  polishing  specula  and  lenses — 
Rev.  W.  Hodgson's  temporary  apparatus  for  polishing  small  specula 
— Grinding  machine  for  spherical  stoppers  of  air-tight  jars  .  1257 

SECT.  5.  Glass-cutting — Glass-cutters' wheels,  mills,  and  polishers  —  rough 
grinding  flutes,  splits,  and  pillars,  on  iron  wheels  fed  with  sand — 
smooth-grinding  on  fine  grit  stones — Polishing  on  willow  wheels,  and 
wheel  brushes — Fitting  stoppers  into  glass  bottles— cutting  glass  drops  1296 


CHAP.  XXXIV.— LAPIDARY  WORK. 

SECT.  1.  Slitting,  cutting,  and  polishing  flat  and  rounded  works — General 
remarks  on  various  apparatus — Ordinary  lapidaries'  bench,  gim  peg, 
slitting  mill — Mortars  for  crushing  and  grinding  diamond  powder — 
Charging  the  slicer,  slicing  gems  and  small  stones — Crane  for  slicing 
large  stones — Flatting  mill,  rough  and  smooth  grinding  flat  surfaces 
— Cutting  the  edges  of  stones  to  definite  forms — cutting  convex  sur- 
faces— cutting  concave  surfaces  and  mouldings — cutting  seal  handles 
— Drilling  large  and  small  holes  .  .  .  .  .  1 302 

SECT.  2.  Cutting  facets — Different  forms  of  facetting — Preparation  of  stones 
for  receiving  facets — Facetting  trap  or  square  cut  stone — Brilliant 
cut— Half  brilliant  cut— Full  brilliant  cut— Trap  brilliant  cut— Double 
brilliant  or  Lisbon  cut — Rose  cut — Star  cut — and  dental  cut — Geneva 
tool  for  facetting — Fictitious  gems — Action  of  heat  on  carnelian,  &c. — 
Pastes. — Metallic  foils — Painted  stones  and  doublets  .  .  .1321 

SECT.  3.  Lapidary  apparatus  for  amateurs — Driven  by  foot- wheel  and  treadle 
— Crane  for  slicing  smaller  large  stones— Apparatus  for  cutting  facets 
mechanically — Table  of  settings  for  the  instrument — Application  to 
facetting  .  ....  1341 


CHAP.  XXXV.— GEM  AND  GLASS  ENGRAVING. 

SFXT.  1.  Introduction — Seal  and  gem  engraving — Seal  engraver's  engine — 
Preparation  of  tools,  or  small  grinding  wheels  of  different  forms- 
Charging  the  tools  with  diamond  powder — Preparing  the  stones — 
Engraving  shield  with  quarterings — Colour  lines — Succession  of  the 
tools  in  gem  and  seal  engraving — Position  of  the  hands — Cutting 
curved  lines — Sinking  flat  surfaces — Position  of  the  stone — Difficulties 
of  manipulation — Mr.  H.  Weigal  on  the  comparative  abilities  of 
English  and  Foreign  gem  engravers— Polishing  engraved  surfaces — 
Qualities  of  different  stones — Taking  proof  impressions  of  seals  .  1348 

SECT.  2.  Cameo  cutting — Effected  by  the  same  general  methods  and  tools  as 
those  employed  in  engraving  in  intaglio — Selection  of  the  stones — 
Onyx,  gem  engraver's  application  of  the  term — Adaptation  of  the 


TABLE    OF    CONTENTS    OF    VOL.  III. 

PAGE 

design    to    the    stone  —  Succession    of   the    processes  —  Spade    for 
smoothing         ........     1365 

SECT.  3.  Glass  engraving — Effected  in  the  same  general  manner  as  seal 
engraving,  but  with  larger  apparatus — Glass  engraver's  tool  and 
wheels — Engraving  works  of  different  kinds  .  .  .  .  3  369 


CHAP.  XXXVI.— VARNISHING  AND  LACKERING. 

SECT.  1 .  Preparation  of  the  varnishes — General  qualities  of  the  resins  com- 
monly used  hi  making  varnishes,  Anime,  amber,  copal,  lac,  saudarac, 
mastic,  damar,  and  common  resin — Vehicles  for  varnishes — Clarifying 
and  boiling  linseed  oil— Oil  of  turpentine — Alcohol,  common  tests  for 
strength,  and  methods  of  concentrating — Preparation  of  oil  varnishes 
— Apparatus  employed  in  making  small  quantities — General  routine  of 
the  process — Fine   copal  varnishes — Cabinet,  carriage,  and  wainscot 
varnishes — Amber   varnish — Preparation   of    spirit  and   turpentine 
varnishes,  with   and  without  the  employment  of  heat — White  and 
brown  hard    spirit  varnishes — Hardwood  lacker — French  polish — 
Bleaching  lac  varnishes — Lackers  for  brass — methods  of  colouring — 
Mastic  and  turpentine  varnishes — Crystal,  paper,  water,  sealing  wax, 
and  black  varnishes       .......     1374 

SECT.  2.  Application  of  varnishes — Spirit  varnishing — necessity  of  dry  and 
warm  atmosphere — varnishing  flat  surfaces — polishing  and  painting 
varnished  works — Japanning,  black,  brown,  and  ornamented  works — 
Lackering  brass,  &c. — methods  of  heating — Lackering  flat  works — 
management  of  the  brush — Lackering  circular  works  in  the  lathe — 
Dipping  and  bronzing  ornamental  brass  works — Lackering  or  polishing 
hardwood  turned  works — French  polishing — Indian  varnishes  for 
Burmese  ware,  palanquins,  and  furniture  ....  1399 

GENERAL  INDEX  of  Vols.  I.  to  III.  1420 


ERRATA, 

Page 

1027,  line  10  from  bottom,  for  This,  read  Thus. 

1067,  line  12  from  bottom,  for  Chap.  XXXIII.,  Sect.  2,  read  Chap.  XXXIL, 

Sect.  3. 

1078,  line  11  from  bottom,  for  Durbec,  read  Purbec. 
1 151,  line    4  from  top,  for  off,  read  of. 
1224,  line    1  at  top,  for  leve,  read  level. 
1368,  line  14  from  bottom,  for  soft  iron,  read  soft  iron  wire. 


TURNING 


MECHANICAL    MANIPULATION. 


VOL.  III. 

ABRASIVE  AND  MISCELLANEOUS  PROCESSES,  WHICH  CANNOT 
BE  ACCOMPLISHED  WITH  CUTTING  TOOLS. 


CHAPTER  XXXI. 

GENERAL    REMARKS    UPON    ABRASIVE    PROCESSES. 
INTRODUCTION. 

THE  third  volume,  which  is  now  to  be  commenced,  refers  to 
a  class  of  operations  entirely  dissimilar  to  those  which  have  been 
described  in  the  foregoing  pages;  as  the  former  descriptions  and 
instructions  have  referred  alone  to  the  treatment  of  such  mate- 
rials as  admit  of  being  cut  with  steel  tools.  In  page  12  of  the 
Introduction  to  the  first  volume  of  this  work,  it  is  stated  that — 

"  The  third  volume  will  be  devoted  to  the  explanation  of 
abrasive  processes ;  namely,  those  for  restoring  or  sharpening  the 
edges  of  cutting  tools ;  those  for  working  upon  substances  to 
which,  from  their  hardness  or  crystalline  structure,  the  cutting 
tools,  (made  of  hardened  and  tempered  steel,)  are  quite  inap- 
plicable ;  and  also  to  the  modes  of  polishing,  which  may  be  viewed 
as  a  delicate  and  extreme  application  of  the  abrasive  process, 
and  the  final  operation  after  the  cutting  tools,  and  lastly,  to  the 
ordinary  modes  of  staining,  lackering,  varnishing,  and  other 
miscellaneous  subjects/' 


1027         COMPARISON    OF    ABRASIVE    AND    CUTTING    PROCESSES. 

In  addition  to  the  broad  distinction  between  the  processes  which 
have  been  hitherto  described,  and  that  are  performed  with  cutting 
tools  of  steel,  there  is  another  conspicuous  difference,  namely, 
that  in  works  executed  by  cutting,  the  material  is  mostly  removed 
in  chips  and  fragments,  which  in  the  case  of  woods  may  be 
burned  as  fuel,  or  in  metals  usually  admit  of  being  reunited  by 
fusion,  and  again  converted  into  ingots,  bars,  or  sheets,  for  sub- 
sequent use  in  the  arts, — whereas  in  the  second  class  of  effects 
now  to  be  considered,  or  those  of  abrasion  by  various  frictional 
processes,  the  removed  materials  are  ground  to  powder,  and  are 
mostly  unsuited  to  further  use. 

On  examination  of  the  various  abrasive  processes,  and  of 
which  grinding  for  the  production  of  form,  and  polishing  for  the 
production  of  surface,  may  be  considered  as  the  extremes,  it  will 
be  seen  there  are  in  every  case  of  abrasion  three  distinct  points 
to  be  considered. 

First,  the  substances  that  are  to  be  ground  or  polished. 
Secondly,  the  materials  or  abrasive  powders  by  the  successive 
employment  of  which  different  substances  are  polished. 

Thirdly,  the  tools  or  apparatus  by  the  agency  of  which  abrasive 
substances  are  applied  to  the  objects  to  be  ground  or  polished. 

Much  variety  necessarily  exists  under  all  three  of  these  heads, 
and  sometimes  the  very  same  substance  may  be  referred  to  all 
of  them  ;  for  example — glass  is  frequently  polished,  as  in  plate 
glass,  cut  glass,  and  lenses. — Glass  is  frequently  used  as  a  polish- 
ing material  when  pulverized  and  glued  upon  paper. — And  glass 
is  also  frequently  used  by  watchmakers  and  some  other  artizans, 
as  a  tool  or  rubber  through  the  medium  of  which,  some  of  the 
polishing  powders  are  applied  to  metal  works  in  the  act  of  polish- 
ing them. 

The  same  thing  may  be  observed  of  iron. — This  metal  in  its 
various  metallic  forms  is  continually  ground  and  polished. — An 
iron  disk  is  used  with  diamond  powder  under  the  name  of  a 
skive,  as  the  lap  whereby  diamonds  for  jewellery  are  polished, — 
and  iron  when  reduced  to  the  form  of  the  peroxide  or  crocus,  is 
used  for  very  many  purposes  in  the  arts,  and  amongst  others  for 
polishing  the  specula  of  reflecting  telescopes. 

By  way  of  condensing  the  numerous  particulars  that  are  to  be 
offered  under  these  several  heads  and  rendering  them  easy  of 
access  and  comparison,  they  will  be  arranged  in  alphabetical 


PRELIMINARY    OBSERVATIONS    ON    GRINDING    AND    POLISHING.    1028 

form  in  a  "  Descriptive  Catalogue  of  the  Apparatus  Materials 
and  Processes  for  Grinding  and  Polishing,  commonly  employed 
in  the  Mechanical  and  Useful  arts." 

The  catalogue  will  be  found  to  contain  much  general  infor- 
mation upon,  and  many  practical  examples  of  abrasive  processes, 
and  will  be  followed  by  one  chapter  on  the  grinding  and  sharpen- 
ing of  tools  of  various  kinds  ; — one  chapter  on  the  figuration  of 
materials  by  abrasion, — in  which  will  be  described  under  distinct 
sections,  some  of  the  modes  of  producing  plane  surfaces,  cylin- 
drical and  conical  surfaces,  spheres  and  spherical  surfaces,  and 
various  mixed  and  arbitrary  forms.  After  which,  two  other 
chapters  will  relate  respectively  to  the  art  of  the  lapidary,  and 
those  of  the  engravers  on  glass  and  gems, — which  several  chap- 
ters will  be  materially  assisted  by  the  matter  contained  in  the 
alphabetical' catalogue, — before  proceeding  to  which  it  is  pro- 
posed to  add  a  few  explanatory  remarks  on  the  three  classes  of 
information  contained  in  the  catalogue. 


SECT.  I. PRELIMINARY  OBSERVATIONS    ON    GRINDING    AND    POLISHING. 

First,  on  the  substances  that  are  to  be  ground  and  polished. 

The  objects  or  substances  the  grinding  and  polishing  of  which 
are  described,  will  be  found  to  include  nearly  all  those  materials 
from  tbe  vegetable,  animal,  and  mineral  kingdoms,  which  are 
commonly  used  in  the  mechanical  arts ;  those  especially  of  which 
mention  has  been  made  in  the  first  volume  of  this  work  in 
reference  to  their  preparation  and  figuration  by  means  of  cutting 
tools,  so  far  as  regards  the  substances  which  admit  of  being 
subsequently  polished.  To  these  will  be  added  the  cutting, 
grinding  and  polishing  of  various  hard  and  crystalline  bodies  on 
which  cutting  tools  are  ineffective. 

Part  of  these  materials  such  as  the  woods,  ivory,  and  some  of 
the  metals  and  alloys,  marble,  glass,  &c.,  receive  dissimilar  treat- 
ment from  different  classes  of  artizans,  the  principal  variations  of 
practice  will  be  respectively  noticed  and  contrasted  under  their 
respective  heads :  but  it  will  be  readily  imagined  that  many 
unimportant  variations  are  made,  that  are  based  rather  on  pre- 
judice than  necessity,  and  the  insertion  of  which  would  tend 

B    2 


1029 


ANALYSES    OF    POLISHING    MATERIALS. 


perhaps  to  confuse  rather  than  assist,  and  therefore  the  ordinary 
routines  will  be  alone  adverted  to. 


Secondly,  on  .the  materials  or  abrasive  powders,  by  the  suc- 
cessive employment  of  which  different  substances  are  polished. 

The  grinding  and  polishing  materials  used  in  the  arts  will  be 
found  principally  to  consist  of  carbon,  alumina,  and  silex,  in 
various  degrees  of  crystallization  and  admixture,  and  usually 
combined  with  the  oxide  of  iron  and  some  other  substances 
as  may  be  seen  by  their  comparative  analyses  given  in  the 
annexed  table. 


TABLE  OF  THE  ANALYSES  OF  POLISHING  MATERIALS. 


Carbon. 

Alumine. 

Silex. 

Lime. 

Iron. 

Authorities,  &c. 

(1) 

Diamond       .     . 

100- 

(2) 

Sapphire  .     .     . 

98-5 

0-5 

1-0 

Klaproth. 

Ruby   .... 
Corundum 

... 

90-0 
86-5 

7-0 
7-0 

1-2 
4-0 

Chenevix. 
Chenevix. 

Emery  of  Naxos 

86-5 

3-0 

4-0 

Tennant. 

Emery  of  Jersey 
Rottenstone  .     . 

ib-b 

53-83 
86-0 

12-66 
4-0 

1-66 

24-66 

Vauquelin. 
R.  Phillips. 

(3) 

Flint    .... 

0-25 

98-0 

0-5 

0-25 

Water  1-0.    Klaproth. 

Tripoli      .     .     . 

10-0 

90-0 

Trace  of  Iron  and  Lime. 

Tripoli     .     .     . 

... 

1-5 

81-0 

... 

8-0 

/  Water  &  Sulp.  Acid  8-5. 
1  Bucholz. 

Polishing  Slate  . 

4-0 

83-5 

8-5 

1-6 

Water  9-0.    Bucholz. 

Polishing  Slate  . 

7-0 

66-5 

1-25 

2-5 

J  Water  19.    Magnesia  1-5. 
1  Klaproth. 

Bohemian  Stone 

1-0 

79-0 

1-0 

4-0 

Water  14-0     Bucholz. 

Turkey  Hone     . 

... 

3-33 

72-0 

1333 

... 

Carbonic  Acid  10-33.  Holme. 

Pumice  Stone    . 

16-0 

70-0 

2-5 

0-5 

("Potash  6-5,    Water    3-0. 
\  Berthier. 

CO 

Oxide  of  Iron     .j 

69-22 

Oxygen  30-78.    Berzelius. 

Oxide  of  Tin      .'      ... 

/Tin  78-34.    Oxygen  21  -66. 
1  J.Davy. 

Chalk  .... 

... 

56-5 

f  Carbonic  Acid  43-0. 
\  Water  0-5.     Bucholz. 

Carbon  in  its  purest  and  most  crystalline  form  constitutes  the 
diamond,    the   hardest   substance   in  nature,  and  which   in   the 


PRINCIPAL    COMPONENTS    OF    POLISHING    MATERIALS.  1030 

pulverized  state  is  variously  employed,  as,  for  example,  in  the 
polishing  of  diamonds  for  jewellery ;  in  the  configuration  of  the 
rubies  and  sapphires  used  for  the  pivot  holes  of  watches  and 
chronometers ;  diamond  powder  is  also  used  by  the  lapidary  in 
slitting  all  stones,  of  course  including  even  those  which  admit 
of  being  polished  by  abrasive  powders  of  inferior  hardness  to  the 
diamond.  Carbon,  in  another  of  its  conditions,  also  constitutes 
charcoal,  and  which,  probably  from  the  minute  particles  of  silex 
disseminated  throughout  its  substance,  is  employed  in  polishing 
copper  and  others  of  the  softer  metals. 

Alumina  when  highly  crystallized  is  the  basis  of  the  ruby, 
sapphire,  and  other  gems  which  are  next  in  hardness -to  the  dia- 
mond. This  earth,  with  the  addition  of  a  little  silex  and  iron, 
constitutes  the  principal  part  of  corundum,  emery,  and  rotten- 
stone  ;  abrasive  materials  that  are  largely  employed  in  grinding 
and  polishing  the  harder  metals  and  mineral  substances.  Alu- 
mina, when  decomposed,  is  the  basis  of  most  of  the  clays  and 
loams,  some  of  which,  under  different  names,  are  likewise  used 
in  abrasive  processes.  It  is  fortunate  for  the  mechanical  arts, 
that  emery,  which  is  nearly  the  hardest  and  most  useful  of  all 
abrasive  substances,  is  also  found  in  sufficient  abundance  to  serve 
for  every  required  application. 

Silex,  in  its  crystalline  form,  and  variously  coloured,  assumes 
the  names  of  quartz,  amethyst,  rock  crystal,  flint,  agate,  and 
when  in  a  disentegrated  state,  that  of  sand.  Silex,  with  the 
addition  of  a  little  alumina  and  foreign  matters,  constitutes  also 
the  major  part  of  the  abrasive  materials  known  as  grit  or  grind- 
stones, rubstones,  hones  and  slaty  stones,  pumice  stone,  tripoli, 
and  some  others,  all  of  which  are  softer  than  those  mineral  sub- 
stances which  are  composed  principally  of  alumina. 

Of  the  siliceous  abrasives,  the  gritty  and  slaty  stones  are  very 
largely  employed  in  the  formation  and  sharpening  of  tools ; 
pumice-stone,  tripoli,  and  others  for  polishing  metallic  and  other 
substances,  softer  than  those  which,  from  their  superior  hardness, 
require  the  employment  of  emery  and  rottenstone,  abrasives  that 
have  alumina  for  their  common  base. 

To  those  abrasive  materials  of  which  carbon,  alumina,  and 
silex  form  the  base,  may  be  added  the  oxide  of  iron  used  under 
the  names  of  crocus  and  rouge,  and  the  oxides  of  tin  and  lead,  or 
putty  powders,  these  are  artificially  prepared  ;  and  a  few  mineral 


1031  APPLICATION    OF    ABRASIVE    MATERIALS. 

substances  of  no  great  importance  as  abrasives  are  used  without 
any  preparation,  such  as  lime  and  chalk. 


Thirdly,  on  the  tools  or  apparatus,  by  the  agency  of  which 
abrasive  substances  are  applied  to  the  objects  to  be  ground  or 
polished. 

Some  of  the  abrasive  substances  are  employed  in  the  solid 
forms  in  which  they  are  first  obtained,  as  the  grindstone,  oil- 
stone, hones,  charcoal,  Dutch  rush,  and  fish  skin ;  a  few  are 
pulverized  and  mixed  with  various  cements,  thus  the  effective 
grindstone  and  razor  hone  of  the  Hindoo  are  corundum  mixed 
with  melted  gum  lac,  and  moulded  into  form  ;  wax  and  crocus 
similarly  mixed  are  used  in  optical  works  amongst  ourselves ; 
and  of  late  years  emery  has  been  reunited  into  factitious  stones. 
But  metal,  wood,  paper,  leather,  cloth,  or  bristles,  are  the  more 
common  implements  or  vehicles,  by  aid  of  which  the  several 
powders  are  applied  in  a  variety  of  ways,  after  the  powders  have 
been  carefully  separated  into  grains  of  similar  magnitude,  the 
sizes  of  which  must  be  proportioned  to  the  perfection  of  the 
surface  to  be  produced,  and  with  a  gradual  transition  from  coarse 
to  fine.  This  succession  is  adopted  upon  the  same  principle  as  that 
in  filing  a  coarse  file  is  first  used,  because  it  may  be  made  to 
act  rapidly;  but  as  the  form  of  the  work  becomes  gradually 
developed,  a  second  cut  file,  a  smooth,  and  lastly,  a  superfine 
file  is  used,  and  which  progressive  mode  of  action  is  in  no  case 
more  distinctly  seen  in  works  of  polishing,  than  in  the  manu- 
facture of  a  highly  finished  razor,  which  is  described  under  the 
head  Cutlery  in  the  following  Catalogue. 

The  grinding  powder  is  of  course  always  harder  than  the 
substance  to  be  ground,  whereas  the  implement  or  grinding  tool 
is  softer,  and  generally  agrees  in  form  with  the  analogous  cutting 
or  moulding  tools  used  for  producing  work  of  corresponding 
shapes  in  other  substances,  as  practised  in  different  branches  of 
the  mechanical  arts.  Thus  turned  works  are  often  polished  with 
blunt  factitious  turning  tools  of  wood  supplied  with  the  powders; 
flat  works  require  artificial  saws,  files,  and  planes ;  a  convex 
surface  requires  a  concave  grinding  tool,  and  so  on. 


IMPORTANCE    OF    CLEANLINESS    IN    POLISHING.  1032 

Cleanliness  should  be  most  scrupulously  observed  in  polishing. 
This  remark  may  appear  misemployed  as  regards  a  process  in 
which  various  dark-coloured  powders,  &c.  are  mingled  with  oil 
or  water  somewhat  like  the  pigments  used  by  artists,  and  are  so 
employed,  that  the  hands  must  almost  inevitably  become  more 
or  less  soiled  ;  but  that  degree  of  care  and  order  must  at  any 
rate  be  adhered  to,  which  will  entirely  avoid  the  different  powders 
and  materials  becoming  mixed.  The  finest  powder,  if  mingled 
with  the  coarse,  would  be  comparatively  inert  and  harmless,  but 
a  grain  or  two  of  the  coarse  powders,  if  accidentally  present 
along  with  the  fine,  would  inflict  deep  scratches,  and  completely 
nullify  the  efforts  at  obtaining  a  highly  polished  surface. 

On  this  account  it  is  desirable  not  only  to  keep  the  various 
polishing  tools  and  powders  carefully  separated  in  boxes  or 
bottles,  but  also  before  proceeding  to  each  finer  stage  of  the 
process,  carefully  to  wipe  or  even  to  rinse  the  work  in  water, 
for  the  entire  removal  of  all  the  previous  materials  employed  in 
the  earlier  stages  of  polishing. 

Having  advanced  these  preliminary  and  general  remarks,  we 
shall  at  once  proceed  to  the  descriptive  and  general  Catalogue, 
deferring  until  the  subsequent  chapters  a  variety  of  additional 
matters  of  a  more  specific  character. 


SECT.  II. 

DESCRIPTIVE   CATALOGUE 

OF    THE 

APPARATUS,  MATERIALS,  AND  PROCESSES 

FOR 

GRINDING   AND   POLISHING, 

COMMONLY  EMPLOYED 

IN    THE 

MECHANICAL  AND  USEFUL  ARTS. 


N.B.— The  descriptions  of  the  Mineral  Substances,  are  for  the  most  part  extracted  or  modified 
from  those  given  in  Wm.  Phillips's  Mineralogy,  3rd  edition,  London,  1823. 


AGATE.  Some  of  the  uses  of  Agate  in  the  mechanical  and  useful  arts  are  described 
in  Vol.  i.  page  173,  and  this  substance  although  much  harder  than  Carnelian 
is  cut  and  polished  precisely  after  the  same  manner,  and  which  process  is 
fully  described  under  the  head  CARNELIAN  in  this  Catalogue. 

ALABASTER.  The  general  modes  of  working  Alabaster  with  saws,  chisels,  files, 
and  turning  tools,  as  regards  its  configuration,  are  described  in  pages  164-5 
of  the  first  volume,  but  this  substance  is  polished  quite  differently  by  the 
sculptor  in  chiselled  or  carved  works,  by  the  marble  worker  in  turned  works, 
and  by  the  lapidary  in  small  objects  of  bijouterie  and  vertu  ;  it  is  therefore 
proposed  briefly  to  describe  these  three  several  modes. 

1. — ALABASTER. — CHISELLED  OR  SCULPTURED  WORKS.  The  dull  or  dead  parts  of 
sculpture,  after  having  been  carved  with  chisels,  as  more  fully  described 
under  the  head  marble,  are,  1st,  smoothed  with  bent  rasps  and  files,  known 
as  rifflers,  and,  2ndly,  are  afterwards  scraped  with  a  triangular  scraper. 
3rdly,  they  are  additionally  smoothed  with  fish  skin  or  glass  paper,  and, 
4thly,  with  Dutch  rush  used^  with  water. 

In  some  few  instances  carved  works  are  polished,  or  else  the  ground  alone 
from  which  the  figures  are  relieved  is  polished  by  way  of  contrast,  in  such 
cases  after  the  four  previous  stages,  the  parts  to  be  polished  are  wrought 
with  the  end  of  a  stick  of  deal  or  other  soft  wood,  supplied  with  Trent  sand 


APPARATUS,    ETC.,    FOR    GRINDING    AND    POLISHING.  1034 

and  water,  and  used  as  a  pencil  or  brush  with  small  circular  strokes,  and 
afterwards  with  a  stick  and  putty  powder  with  water,  just  the  same  as  in 
corresponding  works  of  marble,  which  are  fully  treated  under  that  head  in 
this  Catalogue. 

2. — ALABASTER. — TURNED  AND  POLISHED  WORKS.  Mr.  Hall  of  Derby  has  kindly 
furnished  the  author  with  the  following  outline  of  his  usual  practice.  "  When 
the  article  is  finished  with  the  turning  tool,  take,  1st,  a  piece  of  very  fine 
soft  sandstone,  (found  in  Derbyshire  in  thin  beds  in  the  red  marl  formation,) 
and  apply  it  with  water  to  the  work,  whilst  it  is  in  quick  revolution  moving 
the  stone  all  over  until  there  is  worked  up  'a  body  of  mud  ;  2ndly,  take  a  wet 
rag  and  work  this  sludge  well  on  the  alabaster,  then  wash  the  work  clean  ; 
and  3rdly,  apply  a  rag  charged  with  putty  powder  and  water,  until  there  is 
a  gloss  upon  the  work.  4thly  and  lastly,  apply  another  rag  charged  with  a 
mixture  of  putty  powder,  and  soap  and  water,  for  a  short  time  and  wipe  the 
alabaster  dry  which  completes  the  polish." 

3. — ALABASTER  AS  TREATED  BY  THE  LAPIDARY.  Alabaster  is  far  less  frequently 
wrought  by  the  lapidary  than  the  sculptor,  but  as  it  is  treated  by  the  former 
in  a  manner  somewhat  different  from  the  harder  stones,  it  is  made  one  of 
the  three  general  examples  of  the  lapidary's  art,  introduced  into  this  cata- 
logue, namely,  the  working  of  Alabaster ;  the  working  of  Carnelian  ;  and  the 
working  of  Sapphire ;  which  substances  differ  greatly  in  hardness.  To 
these  three  descriptions  are  appended  lists  of  the  principal  stones  and 
other  substances  that  are  similarly  treated,  by  Mr.  Ward  and  other 
lapidaries,  whom  the  author  has  consulted.  In  the  Chapter  on  Lapidary 
Work  these  outlines  will  be  filled  up,  and  the  general  practice  of  this  curious 
and  interesting  art  will  be  considered  somewhat  more  at  length. 

In  working  Alabaster  to  the  required  forms  the  lapidary  first  employs  as 
usual  the  slitting  mill,  which  is  a  thin  plate  of  iron  fixed  on  a  vertical  spindle, 
and  made  to  revolve  with  moderate  velocity,  the  edge  of  the  slicer  is  charged 
with  diamond  powder,  and  lubricated  with  the  Oil  of  Brick.  This  instru- 
ment which  may  be  considered  as  the  circular  saw  for  small  stones,  is 
used  with  light  pressure  and  plenty  of  brick  oil. 

Secondly  the  alabaster  is  roughed,  or  roughly  ground  on  what  the  lapidary 
terms  a  roughing  or  lead  mill,  namely  a  flat  circular  plate  of  lead,  fixed  on  "a 
spindle  similar  to  that  of  the  slicer,  the  milljor  lap  therefore  travels  in  a 
horizontal  plane,  and  is  abundantly  supplied  with  coarse  emery  and  water  by 
means  of  a  brush.  The  stone  is  moved  to  and  from  the  center  of  the  rapidly 
revolving  lap,  until  all  the  marks  from  the  slitting  mill  are  removed,  and  the 
stone  is  reduced  to  a  flat  surface. 

Thirdly  the  alabaster  is  smoothed  on  the  same  lead  mill  with  flour  emery, 
but  prior  to  smoothing  the  stone,  the  grains  of  the  coarse  emery  previously 
used,  and  that  remain  on  the  lap,  are  rubbed  down  fine  with  a  smooth  lump 
of  emery  stone.  It  would  apparently  be  a  better  practice  to  use  two  different 
laps,  and  together  with  them  emery  of  two  different  sizes  ;  as  in  the  first 
place,  the  operation  of  smoothing  the  mill,  is  tedious,  it  also  tends  to  wear 


1035        DESCRIPTIVE    CATALOGUE   OF    APPARATUS,    MATERIALS, 

away  the  lap  towards  the  edge,  thus  degenerating  the  plane  or  flat  surface 
into  an  irregularly  coned  surface,  with  which  it  is  impossible  to  grind  works 
accurately  flat ;  and  moreover  if  any  coarse  grains  of  emery  are  left  in  the 
lap,  they  greatly  retard  the  smoothing,  and  consequently  the  polishing  also. 
Indeed  it  will  be  found  a  most  erroneous  practice,  to  hurry  over  any  one 
process  with  the  intention  of  making  up  for  it  in  the  next,  for  as  each  stage 
of  the  work  requires  successively  finer  polishing  powders,  the  various  steps 
should  be  continued  the  proportional  times,  or  ultimate  success  will  be  more 
tediously,  if  at  all  attained. 

As  it  is  difficult  to  polish  alabaster  and  substances  equally  soft  on  the 
inelastic  lead  lap  with  rottenstone,  (the  means  usually  employed  for  harder 
stones,)  the  following  is  the  course  ordinarily  followed.  After  the  roughing 
mill  has  been  used,  the  stone  is  smoothed  on  a  wood  mill  or  a  disk  of  maho- 
gany used  with  flour  emery  and  water  ;  on  account  of  the  greater  elasticity 
of  the  wood  mill,  and  the  slight  roughness  of  its  face  from  the  rubbing  up  of 
the  fibres,  it  acts  more  quickly  and  satisfactorily  than  the  metal  tool. 

Fourthly  the  earlier  stage  of  the  polishing  is  accomplished  on  a  list  mill 
with  pumice-stone  and  water,  but  as  the  list  which  is  wound  on  spirally  is 
very  elastic,  flat  works  must  be  lightly  applied,  or  they  will  sink  into  the  soft 
face  of  the  list  mill  and  become  rounded  at  the  edges. 

Fifthly  the  polishing  is  completed  on  a  leather  lap,  or  a  thick  piece  of  buff 
leather  pasted  securely  on  a  wooden  disk,  and  supplied  with  fine  putty  powder 
and  water.  Sometimes  indeed  the  naked  hand,  and  a  little  moistened  putty 
powder  are  finally  used  for  the  last  polish. 

These  several  mills  or  laps  are  more  particularly  described  under  the 
article  WHEELS  in  this  Catalogue. 

The  following  substances  are  worked  by  the  lapidary  in  nearly  or  exactly 
the  same  manner  as  Alabaster,  and  descriptive  articles  are  severally  intro- 
duced in  the  Catalogue  upon  these  particular  substances,  pointing  out  also 
any  peculiarities  of  method  pursued  either  by  the  lapidary  or  other  artizan, 
as  the  case  may  be,  in  working  them. 


(Substances  treated  by  the  Lapidary  like  Alabaster.) 


Amber. 
Cannel  Coal. 
Coral. 
Enamels. 
Glass. 


Jet. 
Lava. 
Malachite. 
Mother  of  Pearl. 
Nacreous  Shells. 


Opal. 

Potstone. 

Satinstone. 

Steatite. 

Turquoise. 


4. — CLEANING  ALABASTER. — Ornamental  works  in  alabaster  that  have  become  soiled 
are  sometimes  cleaned  hi  the  following  simple  manner  : — The  object  is  first 
immersed  in  plain  spring  water  for  four  or  five  days,  the  water  is  then  changed 
and  a  small  quantity  of  lime  is  added,  the  alabaster  is  allowed  to  remain 
in  this  solution  for  a  further  period  of  four  or  five  days,  after  which  it  is  only 
necessary  to  thoroughly  rinse  the  object,  which  is  allowed  to  dry  gradually  in 
the  open  air,  and  the  process  of  cleaning  is  completed.  Should  the  alabaster 


AND    PROCESSES    FOR    GRINDING    AND    POLISHING.  1036 

have  been  very  much  soiled,  a  single  course  of  the  above  treatment  may  fail 
to  restore  the  original  whiteness  ;  hi  this  case  the  process  is  repeated,  and  in 
extreme  instances  a  third  application  is  sometimes  necessary.  Earthenware 
pans  are  the  most  suitable  vessels  to  be  employed,  as  wooden  tubs,  especially 
those  of  oak,  are  almost  certain  to  stain  the  alabaster. 

Objects  that  consist  of  several  pieces  will  be  separated  by  the  above  pro- 
cess ;  they  are,  therefore,  lastly,  reunited  with  plaster  of  Paris,  all  the  parts 
to  which  the  plaster  is  to  be  applied  being  first  moistened  with  water  to 
ensure  the  adhesion  of  the  plaster. 

In  the  original  working  and  finishing  of  the  alabaster,  all  the  pores  or  grain 
of  the  stone  become  filled  with  the  fine  powder  produced  in  polishing,  and 
which  gives  the  alabaster  a  more  compact  surface  than  it  would  otherwise 
present.  This  powder  is  removed  by  the  above  treatment,  and  the  alabaster 
then  exhibits  its  natural  granular  and  sparkling  appearance :  should  this  be 
objected  to,  the  polish  may  be  renewed  by  the  employment  of  putty  powder, 
applied  upon  a  rag  or  stick  as  described  hi  article  1. 

ALB  AT  A  or  BRITISH  PLATE  of  the  best  kind  is  treated  almost  like  silver  work. 
In  polishing  spoons  made  of  the  inferior  kinds  of  Albata,  the  1st  operation, 
which  is  called  roughing,  is  done  upon  bobs  (see WHEELS,  article  51,)  covered 
with  sea-horse  hide  with  a  plentiful  supply  of  Trent  sand  and  oil ;  2ndly, 
rottenstone  and  oil  is  used  ;  and  3dly,  the  finishing  is  done  upon  bobs  with 
oil  and  very  finely  powdered  lime,  materials  that  are  of  the  cheapest  kind, 
and  require  little  or  no  preparation. 

ALBATA  or  GERMAN  SILVER  is  polished  by  the  mathematical  instrument  makers 
the  same  as  BRASS.     See  that  article,  paragraph  4. 

ALUMINA,  in  a  compact  or  crystalline  form  is  the  base  of  some  very  hard  mineral 
substances  used  in  the  arts,  namely,  emery,  corundum,  sapphire  and  ruby, 
of  which  it  constitutes  from  86^  to  98  per  cent.:  these  are  only  exceeded  in 
hardness  by  the  diamond.  See  the  table,  page  1029. 

AMBER  after  having  been  filed,  may  be  polished  1st  with  Trent  sand,  or  scraped 
Flanders  brick  on  flannel  with  water  ;  2ndly,  rottenstone  with  oil  on  flannel ; 
Srdly,  rottenstone  dry  on  the  hand. 

Turned  works  are  generally  polished  first  with  glass  paper,  and  then  with 
rottenstone  and  oil. 

The  lapidary  works  amber  just  after  the  mode  described  under  Alabaster, 
article  3,  but  necklaces  and  other  ornaments  in  amber  that  are  cut  into 
facets,  are  more  usually  and  better  executed  by  the  gold  cutters,  or  those 
artizans  who  cut  and  polish  facetted  works,  and  by  the  same  routine  as  that 
described  in  the  article  3,  under  the  head  GOLD. 

AMETHYST  or  violet  quartz  is  cut  and  polished  by  the  lapidary  like  CARNELIAN, 
which  see. 


1 037         DESCRIPTIVE    CATALOGUE    OF    APPARATUS,    MATERIALS, 

AQUAMARINE,  called  also  BERYL,  and  ANCIENT  BERYL,  is  of  various  shades  of 
pale  yellow,  green  and  blue,  it  was  so  named  from  its  resemblance  to  sea 
water,  and  is  worked  like  CARNELIAN. 

ASTERIA.     See  SAPPHIRE. 

AVANTURINE,  a  mineral  which  is  found  variously  coloured  and  always  enclosing 
particles  of  mica  ;  the  most  common  colour  of  the  base  is  brown  or  reddish 
brown.  It  is  worked  by  the  lapidary  like  Carnelian,  but  does  not  admit  of 
so  good  a  polish  as  the  imitation. 

2. — FACTITIOUS  AVANTURINE,  which  is  glass  or  paste  enclosing  particles  of  metal 
is  generally  more  close  and  brilliant  than  the  real  stone,  and  was  much  used  in 
common  jewellery,  the  imitation  avanturine  is  cut  and  polished  like  other 
pastes,  as  described  under  the  head  ALABASTER,  article  3.  The  method  of 
making  this  artificial  avanturine  which  is  now  lost,  is  considered  to  have 
originated  with  the  Italian  artists,  this  substance  is  now  very  scarce  and 
much  valued. 

3. — ARTIFICIAL  AVANTURINE  which  is  more  brilliant  than  the  last,  and  used  as  a 
microscopic  object,  is  prepared  from  blue  glass  coloured  by  the  oxide  of 
copper,  which  is  stirred  with  an  iron  rod.  The  oxygen  from  its  superior 
affinity  for  the  latter  metal  quits  the  copper,  and  unites  itself  to  the  iron,  and 
in  the  act  of  resuming  the  metallic  form,  the  copper  partially  crystallizes, 
and  becomes  entangled  in  the  glass.  From  the  striated  condition  the  glass 
assumes  on  being  stirred,  the  bright  and  metallic  picture  is  irregular,  and 
appears  full  of  hills  and  dales,  occasionally  clouded  with  the  dark  coloured 
glass  in  which  no  copper  is  visible.  The  crystallization  may  be  distinctly 
seen  with  a  common  lens  of  half  an  inch  focus. 

BERYL,  a  term  that  designates  amongst  lapidaries  and  virtuosi  a  very  rich  deep 
brown  diaphanous  carnelian  ;  it  is  frequently  engraved  into  intaglios,  just 
after  the  manner  of  carnelian  generally. 

BETEL-NUTS,  when  turned,  are  in  general  polished  only  with  fine  glass  paper, 
and  a  few  of  their  own  shavings  ;  whiting  and  water  may  be  used  as  for 
Ivory. 

"  BLOODSTONE  is  a  very  hard,  compact  variety  of  haematite  iron  ore,  which 
when  reduced  to  a  suitable  form,  fixed  into  a  handle,  and  well  polished,  forms 
the  best  description  of  burnisher  for  producing  a  higher  lustre  on  gilt  coat- 
buttons,  which  is  performed  in  the  turning  lathe  by  the  Birmingham  manu- 
facturers. The  gold  on  china  ware  is  burnished  by  its  means.  Burnishers 
are  likewise  formed  of  agate  and  flint ;  the  former  substance  is  preferred  by 
bookbinders,  and  the  latter  for  gilding  on  wood,  as  picture-frames,  &c." — 


BLOODSTONE,  the  appellation  sometimes  employed  by  the  lapidary  and  jeweller,  to 
distinguish  a  dark  green  stone   usually  containing  red   spots,  whence  its 


AND    PROCESSES    FOR    GRINDING    AND    POLISHING.  1038 

popular  name  of  bloodstone  ;  it  is  mineralogically  known  as  the  Heliotrope, 
and  is  considered  as  a  variety  of  chalcedony  :  this  stone  is  worked  exactly 
like  CARNELIAN,  but  is  much  harder  and  takes  longer  to  polish. 

BOB,  a  familiar  name  used  at  Birmingham,  for  small  leather  polishing  wheels,  with 
rounded  edges,  each  made  entirely  of  a  thick  piece  of  lull-neck,  or  sea-cow 
leather,  perforated  to  receive  the  spindle,  and  used  in  polishing  the  insides  of 
the  bowls  of  spoons  and  other  articles.  See  WHEELS,  article  52. 

BONE. — After  the  turning  tool  or  scraper  has  been  used,  bone  is  polished,  1st,  with 
glass  paper,  2ndly,  with  Trent  sand  or  Flanders'  brick  with  water  on  flannel  ; 
3rdly,  whiting  and  water  on  woollen  rag  ;  4thly,  a  small  quantity  of  white  wax 
is  rubbed  on  the  work  with  a  very  quick  motion,  the  wax  fills  the  minute 
pores,  but  only  a  very  small  quantity  should  be  allowed  to  remain  on  the 
work.  Common  bone  works,  such  as  nail  and  tooth-brushes,  are  frequently 
polished  only  with  slaked  lime  used  wet  on  flannel  or  woollen  cloth. 

BOULDERING  STONE.— This  name  is  applied  by  the  Sheffield  cutlers  to  the 
smooth  translucent  flint  pebbles,  found  in  gravel  pits,  with  which  they  smooth 
down  the  faces  of  buff  and  wooden  wheels,  by  abrading  any  large  grains  of 
emery,  or  other  powder  contained  on  their  surfaces.  See  WHEELS,  articles 
43  and  44.  The  bouldering  stones  are  usually  selected  of  about  the  size 
of  a  hen's  or  pigeon's  egg,  and  of  a  flattened  form  ;  and  the  flat  side  becomes 
gradually  worn  down  and  smooth  from  its  continual  application.  The 
term  appears  to  be  derived  from  the  provincial  use  of  the  word  boulder,  to 
denote  the  round  stones  used  in  paving  ;  whence,  also,  boulder-setter  or 
pavior. 

Metal  laps  are  "  bouldered  down ; "  first,  they  are  supplied  with  a  little 
emery  and  oil,  which  is  spread  with  the  fingers,  and  then  pressed  into 
the  metal  and  worn  down  fine  and  smooth  with  the  bouldering  stone,  and 
wood  laps  are  first  anointed  with  flour  emery  or  fine  flour  emery  ;  they 
are  then  well  bouldered,  and  are  lastly  waxed  by  holding  a  small  piece  of  wax 
against  the  revolving  wheel ;  these  processes  greatly  reduce  the  cut  of  the 
powders  ;  and  unless  the  bouldering  stone  is  plentifully  applied  the  colour  or 
high  gloss  cannot  be  produced  on  the  works. 

BRASS  is  finished  by  different  classes  of  artizans,  by  methods  that  are  widely 
dissimilar,  many  of  which  are  described  ;  and  it  may  be  considered  that  the 
same  modes  are  also  suited  to  the  other  alloys,  consisting  principally  of 
copper,  such  as  gun  metal,  electrum,  or  German  silver,  &c.,  particularly  as 
regards  parts  of  machinery  and  mathematical  instruments. 

1. — TURNED  WORKS  IN  BRASS  are  frequently  polished  with  emery  paper  alone, 
two  sizes  of  which  are  mostly  used  with  a  little  oil.  For  plane  and  cylin- 
drical surfaces,  the  emery  paper  is  wrapped  around  a  parallel  piece  of  stick, 
and  for  internal  plane  surfaces  it  is  applied  by  means  of  a  small  cubical  block 


1039         DESCRIPTIVE    CATALOGUE    OF    APPARATUS,    MATERIALS, 

of  wood  ;  these  methods  tend  to  preserve  the  external  angles  from  being 
rounded.  An  additional  lustre  is  given,  if  required,  by  woollen  cloths  with 
oil  and  rottenstone.  When  the  work  is  not  to  be  varnished,  a  minute 
quantity  of  the  polishing  oil  is  left  on,  which  somewhat  prevents  tarnishing. 

The  sliding  tubes  of  telescopes,  after  having  been  cleaned  off  with  fine 
emery  paper,  are  brushed  with  a  revolving  or  wheel  brush,  with  fine 
crocus  and  oil,  and  are  finished  with  a  woollen  rag  and  rottenstone,  nearly 
free  from  oil,  and  rubbed  lengthways,  the  lathe  being  for  the  time  at  rest. 

2. — COMMON  FLAT  WORKS,  after  they  have  been  filed  up,  are  frequently  finished 
first  with  coarse  and  then  with  fine  emery  paper,  which  is  often  used  dry  or 
without  oil,  and  wrapped  around  a  file  or  wooden  rubber.  The  gram  is 
usually  laid  straight,  or  in  one  direction  ;  at  other  times  the  works  are 
coarsely  curled  by  a  circulating  motion  of  the  hand. 

3. SUPERIOR  FLAT  WORKS. — The  brass  plates  for  the  mechanism  of  harps  are 

perhaps  more  carefully  treated  than  any  of  this  kind.  The  plates  of  the 
harp  machinery  are  planed  and  scraped,  the  mechanism  is  then  fitted,  and 
the  second  axes  or  arbors  are  ground  into  their  respective  pivot -holes  with 
fine  oilstone  powder.  The  plates  are  again  carefully  scraped,  after  which 
they  are  polished,  1st,  with"  charcoal  in  the  stick,  to  remove  all  the  marks 
made  with  the  scraper  and  file.  2ndly,  flour  emery  is  dusted  over  the  plate 
from  a  muslin  bag,  and  rubbed  with  a  piece  of  wood  three  or  four  inches 
square,  covered  with  baize  nailed  around  the  edges,  to  serve  as  a  rubber. 
3rdly,  rottenstone  is  similarly  employed  upon  a  rubber  covered  with  two  or 
three  thicknesses  of  fine  woollen  cloth  ;  the  plate  is  then  washed  quite  clean 
and  dried.  4thly,  it  is  finished  with  a  dry  buff  rubber  and  rottenstone  ;  the 
holes  are  then  cleaned  out  with  a  feather  slightly  coated  with  dry  whiting, 
and  finally  the  plate  is  varnished.  In  all  the  processes  it  is  necessary  to 
follow  the  curvature  of  the  plate,  in  order  to  lay  the  gram  in  accordance 
therewith. 

Brass  door-plates  of  the  best  kind  are  treated  with  nearly  the  same  care, 
although  immaterial  variations  are  often  made  in  the  routine. 

4. — FLAT  WORKS  IN  MATHEMATICAL  INSTRUMENTS. — Such  of  these  as  are  in  brass 
and  gun  metal,  when  left  from  a  very  smooth  file  are  prepared  first  with  a 
stick  of  water  of  ayr  stone  ;  and  are  afterwards  finished  with  water  of  ayr 
stone  scraped  to  a  fine  powder,  mixed  with  a  little  oil  to  the  consistence  of 
treacle,  and  applied  with  a  smooth  piece  of  white  deal.  If  the  work  present 
lines  from  the  grain  of  the  wood,  it  is  rubbed  with  the  clean  finger,  or  a  buff 
stick  smeared  with  oil,  the  polishing  stuff  that  remains  on  the  work  being 
sufficient  for  the  concluding  step. 

The  edges  of  work,  after  having  been  drawfiled,  are  scraped  with  a  sharp 
triangular  scraper,  applied  almost  without  pressure,  in  order  to  avoid  utters 
or  indentations  ;  oilstone  powder  with  oil  is  next  used  on  a  piece  of  maho- 
gany, then  scraped  water  of  ayr  stone,  as  above,  and  lastly,  a  buff  stick  with 
dry  rottenstone. 

5. — FLAT  WORKS  CURLED. — These  are  filed,  scraped,  and  stoned,  as  by  the  mathe- 


AND    PROCESSES    FOR    GRINDING    AND    POLISHING.  1040 

matical  instrument  makers.  The  work  is  then  clouded  with  a  piece  of 
charcoal  and  water,  by  means  of  which  the  entire  surface  is  covered  with 
large  curly  marks,  which  form  the  ground.  The  curls  resemble  an  irregular 
cycloidal  pattern,  with  loops  of  from  one  quarter  to  one  inch  diameter, 
according  to  the  magnitude  of  the  work.  Similar,  but  much  smaller  marks 
are  then  made  with  a  piece  of  snake-stone,  blue-stone,  or  even  common  slate 
pencil,  filed  to  a  blunt  point.  The  general  effect  of  the  work  much  depends 
upon  the  entire  surface  being  uniformly  covered,  with  which  view  the  curls 
should  be  first  regularly  continued  around  the  margin,  the  central  parts  are 
then  filled  in  ;  after  which  the  work  is  ready  to  be  varnished. 

The  curled  surfaces  are  desirable,  in  so  much  as  any  little  accidental 
injuries  or  rubbing,  arising  from  the  continued  use  of  the  articles,  are  less 
observable  upon  curled  surfaces  than  upon  similar  pieces  laid  with  an  even 
grain ;  and  the  curled  parts  mixed  with  the  bright  edges  have  a  good  effect. 
The  mode  was  introduced  by  the  author's  father. 

6. — WATCHWORK  IN  BRASS. — Flat  works  of  medium  character,  after  having  been 
filed,  are  polished,  1st,  with  a  stick  of  blue  stone  and  water,  and  2ndly,  with 
a  slip  of  box  wood,  with  the  unguent  obtained  by  rubbing  two  pieces  of 
blue-stone  together  with  oil.  The  best  and  flattest  watch  works,  after  1st, 
the  blue-stone,  are  polished  2ndly  with  pewter  and  red  stuff  or  crocus,  and 
3rdly  with  a  piece  of  tortoiseshell,  horn,  or  ivory,  supplied  with  very  fine 
red  stuff  and  oil. 

Tortoiseshell  is  preferred  for  the  polisher,  as  it  may  be  used  nearly  dry 
and  leaves  the  fewest  streaks  or  shades  hi  the  work  ;  horn  is  next  in  estima- 
tion, and  ivory  the  least  of  the  three ;  each  of  which  materials,  and  also  pewter, 
glass,  &c.,  are  used  in  flat  pieces  from  one  to  two  inches  square,  which  are 
smeared  with  the  powders  mixed  with  oil ;  the  work  is  then  rubbed  on  the 
surface  with  the  fingers,  as  if  it  were  the  muller  used  in  grinding  paint ; 
this  produces  very  flat  surfaces.  The  burnisher  is  sometimes  used  after  the 
powders. 

Most  of  the  brass  work  of  watches  is  gilt  by  water  gilding,  to  prevent  it 
tarnishing  from  the  effect  of  the  atmosphere.  The  polishing  of  the  steel 
part  of  watchwork  is  described  under  the  head  MACHINERY  in  iron  and  steel 
in  this  catalogue,  article  1 3. 

7. — BRAZIERS  WORKS.— The  coppersmiths  and  braziers  adopt  nearly  the  same 
treatment  for  brass  as  for  copper.  Subsequently  to  the  brass  work  having 
been  annealed  for  the  last  time,  and  before  it  is  planished  with  the  hammer, 
it  is  generally  pickled  with  nitrous  acid  diluted  with  very  little  water,  and  then 
scoured  with  coarse  red  tripoli  and  water  to  remove  the  oxidation  caused  by 
the  fire.  The  work  when  planished  is  cleaned  1st  witfi  crocus  and  oil ;  2ndly, 
the  oil  is  rubbed  off  with  whiting  ;  and  3rdly,  the  final  polish  is  given  with 
dry  rottenstone  usually  applied  on  an  old  worsted  stocking. 

8. — STAMPED  WORKS  IN  BRASS,  for  house  furniture,  such  as  finger  plates  for 
doors,  and  numerous  other  objects  stamped  out  of  sheet  brass,  are  treated  in 
a  manner  entirely  different  from  all  the  preceding,  as  the  sheet  brass  when 


1041         DESCRIPTIVE    CATALOGUE    OF    APPARATUS,    MATERIALS, 

carefully  rolled  is  left  very  smooth  and  only  requires  to  be  made  bright.  The 
stamped  works  are  1st  cut  out,  2ndly  figured  between  dies,  in  a  fly  press,  or 
under  a  stamp  hammer  usually  called  a  force,  3rdly  they  are  annealed,  4thly 
coloured  by  immersion  in  an  acid  preparation,  Sthly  washed  and  dried  in  saw- 
dust. The  entire  surface  is  now  of  a  rich  yellow  or  gold  colour  but  dead  or 
dull,  Gthly  the  parts  desired  to  be  bright  are  burnished  with  a  steel  burnisher 
which  is  lubricated  with  water  alone,  or  with  water  having  a  trifling  admix- 
ture of  vinegar  or  beer,  and  7thly  the  work  is  varnished.  The  methods  of 
colouring,  bronzing,  and  varnishing,  stamped  works  and  others  of  the  same 
character,  will  be  hereafter  detailed. 

9. — CAST  WORKS  IN  BRASS  FOR  HOUSE  FURNITURE,  including  lamp  and  gas  fittings. 
These  works  receive  little  or  no  polishing  by  the  ordinary  methods  of 
abrasion  with  powders,  which  would  be  too  tedious  and  expensive  a  process. 
The  smallest  and  commonest  of  the  castings,  after  haring  been  cleaned  by 
the  brass  founder,  in  the  rumble,  are  coarsely  filed  and  then  scraped ;  those 
pieces  which  are  more  carefully  moulded,  as  described  under  fine  casting, 
(vol.  i.  p.  341,)  require  only  the  removal  of  the  rough  edges  or  burrs,  and 
the  tubes  employed  in  gas  works,  &c.,  are  left  sufficiently  smooth  from  the 
draw-plate.  The  several  parts  after  having  been  adapted  together,  by  aid  of 
the  file,  turning  tool,  screws  or  solder,  are  almost  exclusively  decorated  by 
the  processes  of  dipping,  bronzing,  burnishing  and  varnishing  ;  part  of  which 
processes,  as  noticed  in  the  last  article,  will  be  treated  of  towards  the  end 
of  this  volume. 

BRITANNIA  METAL  works,  like  those  in  hard  pewter,  which  this  alloy  con- 
siderably resembles,  after  having  been  turned  are  in  great  measure  finished 
by  the  steel  burnisher  with  an  abundance  of  oil ;  the  final  lustre  is  usually 
given  with  rottenstone  and  oil  on  woollen  rag.  Frequently  a  very  minute  coat 
of  oil  is  left  as  a  defence  to  retard  the  action  of  the  atmosphere,  at  other 
times  the  surfaces  are  thoroughly  brightened  with  dry  whiting,  applied  on 
wash  leather. 

Many  workmen  polish  Britannia  metal  with  Trent  sand  and  oil,  to  the 
exclusion  of  all  other  applications.  This  sand  is  probably  unequalled  as  to 
fineness. 

BRONZE. — The  Bronze  metal,  (copper  and  tin,)  is  now  usually  called  gun-metal,  or 
bell  metal,  according  to  its  proportions,  and  is  polished  after  the  manner  of 
BRASS,  which  see  articles  1  to  5. 

The  colours  of  bronzes,  imitative  of  those  tints  which  occur  on  the  metal 
from  long  exposure  to  the  atmosphere,  are  sometimes  produced  chemically 
in  the  modes  to  be  subsequently  described. 

BRUSH  WHEELS,  circular  revolving  brushes  are  used  with  various  polishing 
materials,  see  WHEELS  articles  65  and  66.  Hand  polishing  brushes  are  also 
used,  which  are  made  almost  like  nail  brushes,  but  many  of  them  are  longer, 


AND    PROCESSES    FOR    GRINDING    AND    POLISHING.  1042 

narrower,  and  also   softer,  especially  such   as   are  used  by  watchmakers, 
jewellers,  and  others. 

BUFF  LEATHER  is  used  in  various  ways  for  polishing  ;  thus  it  is  glued  on  the 
circular  edges  or  plane  surfaces  of  wooden  polishing  wheels,  and  used  with 
coarse  emery,  crocus,  rottenstone,  and  other  powders,  see  WHEELS, 
article  5. 

BUFF  STICKS  are  parallel  rods  of  deal  upon  which  strips  of  buff  leather  are 
fixed,  either  by  means  of  glue,  or  by  folding  the  leather  around  the  ends,  and 
securing  it  by  iron  tacks.  The  buff  sticks  are  principally  used  with  crocus 
and  rottenstone,  both  with  or  without  oil,  and  for  most  of  the  metals  as  well 
as  various  other  substances  ;  in  some  few  cases  the  buff  stick  is  moistened 
with  water,  see  TORTOISESHELL. 
BUFF  WHEELS  are  described  under  the  head  WHEELS,  articles  51  to  53. 

BURNISHER. — This  valuable  instrument  is  in  general  a  piece  of  hardened  steel 
very  highly  polished,  and  when  judiciously  applied  to  the  smooth  surfaces  of 
metals,  it  imparts  to  them,  by  means  of  friction,  or  intimate  contact,  a  polish 
nearly  equal  to  that  which  the  burnisher  itself  possesses. 

2. — THE  ACTION  OF  THE  BURNISHER  appears  to  depend  upon  two  circumstances  ; 
first,  that  the  harder  the  material  to  be  polished  the  greater  lustre  it  will 
receive,  and  the  burnisher  is  commonly  made  of  hardened  steel,  which  exceeds 
in  hardness  nearly  every  metallic  body.  And  secondly,  its  action  de- 
pends on  the  intimacy  of  the  contact,  betwixt  the  burnisher  and  the 
work ;  and  the  pressure  of  the  brightened  burnisher  being,  in  reality,  from 
its  rounded  or  elliptical  section,  exerted  upon  only  one  mathematical  line  or 
point  of  the  work  at  a  time,  it  acts  with  great  pressure  and  in  a  manner 
distantly  analogous  to  the  steel  die  used  in  making  coin  ;  in  which  latter  case, 
the  dull  but  smooth  blank,  becomes  instantly  the  bright  and  lustrous  coin,  in 
virtue  of  the  intimate  contact  produced  in  the  coining  press,  between  the 
entire  surface  of  the  blank  and  that  of  the  highly  polished  die. 

It  by  no  means  follows  however  that  the  burnisher  will  produce  highly 
finished  surfaces,  unless  they  have  been  previously  rendered  smooth,  and 
proper  for  the  application  of  this  instrument ;  as  a  rough  surface  having  any 
file  marks  or  scratches,  will  exhibit  the  original  defects,  notwithstanding  that 
they  may  be  glossed  over  with  the  burnisher  which  follows  every  irregularity  ; 
and  excessive  pressure,  which  might  be  expected  to  correct  the  evil  as  in 
coining,  only  fills  the  work  with  furrows,  or  produces  an  irregular  indented 
surface,  which  by  workmen  is  said  to  loefull  of  utters. 

Therefore,  the  greater  the  degree  of  excellence  that  is  required  in  bur- 
nished' works,  the  more  carefully  should  they  be  smoothed  before  the 
application  of  the  burnisher,  and  which  should  be  cleaned  on  a  buff  stick 
with  crocus  immediately  before  use  ;  and  it  should  in  general  be  applied  with 
the  least  degree  of  friction  that  will  suffice.  Cutlers  mostly  consider  that 
burnishers  for  steel  are  best  rubbed  on  a  buff  stick  with  the  finest  flour 

VOL.  III.  C 


1043        DESCRIPTIVE    CATALOGUE    OF    APPARATUS,    MATERIALS, 

emery ;  for  silver  however  they  polish  the  burnisher  with  crocus  as  usual. 
Most  of  the  metals  previously  to  their  being  burnished  are  rubbed  with  oil 
to  lessen  the  risk  of  tearing  or  scratching  them,  but  for  gold  and  silver,  the 
burnisher  is  commonly  used  dry,  unless  soap  and  water  or  skimmed  milk  are 
employed  ;  and  for  brass  furniture,  water  with  or  without  a  little  vinegar, 
or  else  beer  is  preferred  for  lubricating  the  burnisher. 

3.— THE  MOST  GENERAL  FORMS  OF  BURNISHERS.— The  burnisher  used  by  mechani- 
cians generally,  resembles  in  form  a  file  of  elliptical  section  without  teeth  ; 
it  is  made  particularly  hard  and  well  polished.  For  engravers  in  line  and 
mezzotint,  the  burnishers  are  sometimes  crooked  like  the  horn  of  a  cow  ;  for 
watchmakers  and  others,  they  are  flat  so  as  to  apply  to  pivots,  and  other 
burnishers  for  these  artizans  are  nearly  cylindrical  for  the  interior  surfaces 
of  pivot  holes,  and  which  are  applied  as  in  using  a  polygonal  broach.  For 
ironmongery  a  narrow  piece  of  steel  is  inlaid  in  a  cross  handle  of  wood,  that 
is  used  almost  like  a  spoke-shave,  and  the  pressure  is  increased  by  a  leather 
strap  or  bridle  attached  on  both  sides  of  the  burnisher,  in  the  bend  of  which 
the  workman  places  his  foot,  to  give  the  pressure.  The  same  form  of  bur- 
nisher is  employed  in  Sheffield  for  the  springs  of  pocket  knives,  but  the 
strap  is  generally  omitted. 

The  burnisher  is  sometimes  also  fitted  up  with  a  handle  at  one  end  and 
a  hook  and  staple  at  the  other,  somewhat  like  the  paring  knife  used  by  clog 
makers  and  others  (see  fig.  18,  vol.  1,  page  26).  This  kind,  which  is  called  the 
clog  burnisher,  is  much  used  at  Sheffield,  for  the  backs  and  squares  of  knife 
blades,  which,  after  they  have  been  made  quite  smooth,  rare  moistened 
with  the  tongue  and  burnished  with  the  clog  burnisher,  then  the  work  and 
tool  are  wiped  quite  dry  with  a  clean  linen  cloth,  and  a  very  gentle  dry  bur- 
nishing completes  the  work. 

Fender  makers  and  others  have  the  burnisher  at  the  bottom  end  of  a  pole 
suspended  from  the  ceiling,  or  rather  from  a  long  and  strong  spring  like  that  of 
the  pole  lathe,  or  a  straight  coach  spring  ;  this  enables  them-  to  take  a  very 
long  and  equal  stroke.  The  same  contrivance,  (which  is  also  used  in  calenc 
cloth  by  hand,)  is  nearly  copied,  but  with  a  piece  of  leather  and  emery, 
laying  a  straight  and  dull  grain  on  long  works. 

Burnishers  made  of  flint,  agate,  and  bloodstone  are  used  by  bookbinders 
and  picture  frame  makers,  also  by  silversmiths  and  jewellers,  and  other 
artizans,  see  BLOODSTONE. 

CANNEL  COAL. — In  polishing  flat  works  of  this  material,  such  as  inkstands,  water 
of  ayr  stone  in  the  stick  is  1st  used  with  water  ;  2ndly,  charcoal  dust 
soft  soap  on  a  flannel ;  and  although  3rdly,  for  fine  works  rottenstone  on 
hand  or  flannel  have  been  used,  it  is  better  to  continue  the  second  pro< 
until  the  completion,  adding  only  additional  soft  soap  with  water  as 
lubricator.     For  the  working  of  cannel  coal,  see  vol.  1,  p.  162. 

For  objects  turned  in  the  lathe,  the  water  of  ayr  stone  is  superseded 
emery  paper. 


Lllclli   Ul 

a  very 
idering 
TV,  for 


AND    PROCESSES    FOR    GRINDING    AND    POLISHING.  1044 

The  Lapidary  works  Cannel  Coal  just  as  he  would  Alabaster ;  see  Article  3 
under  that  head. 

CAP. — A  term  used  by  many  of  the  Sheffield  Cutlers  to  designate  wooden  wheels, 
capped  or  surrounded  with  a  ring  of  metal  to  constitute  laps,  the  edges  only 
of  which  are  used,  see  WHEELS,  articles  37  to  47,  where  their  construc- 
tion and  application  are  described. 

CARBON,  when  highly  crystallized,  as  hi  the  diamond,  is  the  hardest  substance  in 
nature,  and  cuts  all  others.  Next  in  hardness  to  the  diamond  are  those 
mineral  substances  having  for  their  bases  alumina,  silex,  and  the  metallic 
oxides  of  iron  and  tin.  See  also  the  articles  on  DIAMOND  and  CHARCOAL. 

CARBUNCLE. — The  stone  that  is  considered  to  have  obtained  this  name,  in 
ancient  as  well  as  in  modern  times,  is  the  Almandine,  or  Precious  Garnet  of 
mineralogy  ;  it  is  usually  polished  en  cabochon,  or  with  a  rounded  surface 
without  facets,  after  the  general  manner  of  oriental  jewellery,  and  is  worked 
like  CARNELIAN,  as  described  in  the  following  article. 

CARNELIAN  is  the  substance  that  has  been  selected  as  the  example  of  the  mode 
of  cutting  and  polishing  stones  of  a  medium  degree  of  hardness,  the  two  other 
examples  being  Alabaster  for  the  softest  stones,  and  Sapphire  for  the  hardest, 
excepting  alone  the  diamond,  which  last  is  worked  in  a  manner  peculiar  to 
itself,  and  is  separately  considered.  As  already  observed,  some  of  these 
subjects  will  be  resumed  more  at  length  in  Chapter  XXXIV.  on  Lapidary 
work. 

1. — CARNELIAN  when  operated  upon  by  the  Lapidary,  is,  1st,  slit  with  the  thin  iron 
slicer  fed  with  diamond  dust  and  moistened  with  brick  oil ;  2ndly,  it  is  rough 
ground  on  the  lead  mill  with  coarse  emery  and  water  ;  and,  3rdly,  it  is 
smoothed  either  on  the  same  lap  rubbed  down  fine,  or  with  a  similar  lap 
used  with  finer  emery  ;  thus  far  the  steps  are  precisely  as  explained  with 
regard  to  Alabaster. 

4thly.  Carnelian  and  stones  of  similar  or  superior  hardness,  and  which 
are  not  smaller  than  about  one  third  of  an  inch  in  diameter,  are  in  almost 
all  cases  polished  on  a  lead  mill  plentifully  supplied  with  rottenstone  and 
water ;  but  this  fine  powder  will  scarcely  adhere  after  the  manner  of  the 
coarser  and  granular  emery,  or  by  simple  pressure,  and  therefore  to  expe- 
dite the  process  the  face  of  the  polishing  lap  is  hacked,  or  jarred,  although 
in  a  manner  quite  different  from  that  pursued  by  the  cutler. 

The  Lapidary  employs  the  blade  of  an  old  table  knife  which  he  holds 
slenderly  between  the  thumb  and  finger,  placed  near  the  middle  of  the  blade, 
while  the  front  part  of  the  edge  rests  on  the  lap,  not  perpendicularly,  but 
slanted  a  little  forwards,  so  as  to  meet  the  lap  edge  foremost  during  its  revo- 
lution: the  unstable  position  of  the  knife  causes  it  to  jump,  vibrate,  or  chatter 
on  the  lap,  and  at  each  jump  it  makes  a  very  slight  furrow  ;  these  fill  the 
face  of  the  mill  with  minute  lines  or  grooves,  that  serve  for  the  lodgement  of 

c  2 


1045        DESCRIPTIVE    CATALOGUE    OF    APPARATUS,    MATERIALS, 

the  finely  powdered  rottenstone.  It  is  however  to  be  observed  that  the  wheel 
should  be  made  first  to  revolve  in  the  one  direction,  and  then  in  the  opposite, 
that  the  marks  of  the  hacking-knife  may  cross  each  other. 

2. Smaller  and  harder  stones  are  more  commonly  polished  on  a  pewter  than  a 

lead  lap,  and  for  the  smallest  and  hardest  stones  a  copper  lap  is  preferred  ; 
but  all  the  polishing  tools,  of  what  metal  soever  they  may  be  made,  are 
hacked  as  above  described,  and  used  with  rottenstone  and  water. 

3. — ROUNDED  OR  CONVEX  STONES,  or  those  said  to  be  cut  en,  cabochon,  whether  of 
Carnelian  or  even  several  of  the  harder  stones,  are  in  many  cases  succes- 
sively wrought  by  means  of  the  wood  mill  with  fine  emery,  the  list  mill  with 
pumice-stone,  and  leather  lap  with  putty  powder,  precisely  as  described  under 
the  head  Alabaster.  This  is  done  on  account  of  the  greater  elasticity  of  these 
apparatus,  which  enables  them  to  ply  more  conveniently  to  the  globular  forms 
of  the  works  to  be  polished,  and  avoid  wearing  them  in  ridges  or  flat  places. 

4. — FACETTED  WORKS  on  all  stones  and  hard  substances,  are  for  the  most  part  cut 
by  the  Lapidary  after  one  of  three  different  modes.  First,  for  pastes  or  arti- 
ficial stones,  and  many  soft  stones,  as  amber,  carnelian,  jet,  &c.,  the  facets 
are  usually  cut  on  a  lead  wheel  with  emery,  and  polished  on  pewter  with 
rottenstone. — Secondly,  for  some  of  a  harder  kind  but  inferior  in  hardness  to 
sapphires,  the  succession  of  tools  is  a  pewter  lap  and  fine  emery  for  the  cut- 
ting, and  a  copper  lap  with  rottenstone  for  the  polishing. — Thirdly,  for 
sapphires,  the  chrysoberyl,  and  rarely  for  some  few  others  likewise,  a  copper 
lap  with  diamond  powder  is  used  for  cutting  the  facets,  and  a  copper  lap 
with  rottenstone  for  polishing  them. — And  fourthly,  with  the  diamond,  two 
stones  are  rubbed  in  a  peculiar  manner  the  one  against  the  other  to  cut  the 
facets,  and  they  are  polished  by  means  of  the  dop,  and  an  iron  lap  or  skive 
fed  with  diamond  powder  ;  this  process  is  more  fully  described  in  vol.  1, 
page  1 76. 

5. — From  the  comparatively  small  size  of  the  stones  and  gems  that  are  cut  into 
facets,  they  cannot  generally  be  held  unassistedly  in  the  fingers,  the  stone  is 
consequently  cemented  centrally  upon  the  end  of  a  round  stick  of  wood 
nearly  like  a  drawing  pencil.  The  stick  when  held  vertically,  gives  the  posi 
tion  for  grinding  the  central  facet  or  table  of  the  stone,  the  stick  is  inclined 
to  a  certain  angle  for  the  eight,  twelve,  or  more  facets,  contiguous  to  the 
table  ;  of  which  facets,  two,  three,  or  four  series  are  commonly  required  at 
different  inclinations,  and,  lastly,  the  horizontal  position  of  the  stick  serves  in 
cutting  the  girdle  or  central  band  around  the  exterior  edge  of  the  stones. 

The  several  inclinations  of  the  stick  on  which  the  stone  is  cemented,  are 
easily  determined  by  placing  the  upper  end  of  the  stick  into  one  of  several 
holes  in  a  vertical  post,  fixed  alongside  the  lap,  and  this  retains  the  inclina- 
tion very  accurately  and  simply,  but  all  these  matters  will  be  further  eluci- 
dated in  the  34th  chapter  on  Lapidary  Work  generally. 

6. — The  following  substances  are  worked  by  the  lapidary  in  nearly  or  exactly 
the  same  manner  as  carnelian,  and  descriptive  articles  are  introduced  in 
the  catalogue  upon  each  of  these  particular  substances,  pointing  out  their 


! 


AND   PROCESSES    FOR    GRINDING    AND    POLISHING. 


1046 


principal  external  features,  and  also  any  peculiarities  of  method,  pursued 
either  by  the  lapidary  or  other  artizan,  as  the  case  may  be,  in  working 
them. 


(SUBSTANCES  TREATED  BY  THE  LAPIDARY  LIKE  CARNELIAN.) 

Agate 

Elvans 

Mina  Nova 

Amethyst 

Emerald 

Onyx 

Aquamarine 

Felspar 

Opal 

Beryl 

Flint 

Pastes 

Bloodstone 

Fluor  Spar 

Peridot 

Brazilian  Topaz 

Garnet 

Plasma 

Carbuncle 

Granite 

Porphyry 

Cat's-eye 

Heliotrope 

Quartz 

Chalcedony 

Jade 

Sard 

Chrysolite 

Jasper 

Sardonyx 

Chrysoprase 

Lapis  Lazuli 

Serpentine 

Crystal 

Marble 

Topazes. 

CAST-IRON. — When  the  parts  of  machinery  that  are  made  in  cast-iron  are 
polished  they  are  treated  as  described  in  tlu's  catalogue  under  the  general 
article  on  MACHINERY  made  of  iron  and  steel. 

THE  FRONT  OF  STOVES,  and  similar  bright  works  in  cast  iron,  are  first  ground 
on  large  grindstones,  and  then  buffed  on  large  revolving  buffs  upon  which 
a  coating  of  emery  has  been  fixed  by  glue.  They  are  sometimes  finished  by  a 
hand  rubber  used  as  a  spokeshave  having  a  piece  of  leather  supplied  with  fine 
emery  and  oil,  but  the  rubbers  suspended  from  the  ceiling  at  the  end  of  a 
powerful  spring,  are  also  very  judiciously  employed  in  these  large  works. 
See  the  end  of  the  article  BURNISHER. 

FIRE  IRONS  are  often  cast  in  iron  that  is  afterwards  rendered  malleable ;  which  is  a 
rapid  way  of  producing  beautiful  form,  combined  with  strength  and  a  certain 
measure  of  flexibility,  see  vol.  1,  page  259,  the  works  are  afterwards  case- 
hardened,  that  they  may  admit  of  a  better  lustre,  and  which  is  generally 
given  by  grindstones,  glazers,  buffs  and  brushwheels,  much  the  same  as  in 
cutlery  but  on  a  larger  scale. 

CAT'S-EYE,  a  mineral  consisting  of  quartz  enclosing  amianthus  or  asbestos,  and 
thence  possessing  the  property  emphatically  described  by  the  French  as 
chatoyant ;  the  cat's-eye  is  polished  just  like  AGATE  or  CARNELIAN. 

CHALCEDONY,  a  name  applied  to  many  siliceous  minerals  including  as  varieties 
the  onyx,  sard,  sardonyx,  plasma,  heliotrope,  and  chrysoprase  :  they  are 
wrought  like  CARNELIAN,  which  see. 

CHALK  when  simply  scraped,  or  else  crushed  under  the  hammer,  is  occasionally 
used  in  polishing  bone,  ivory,  and  some  few  soft  substances,  it  cuts  much 


1045        DESCRIPTIVE    CATALOGUE    OF    APPARATUS,    MATERIALS, 

the  finely  powdered  rottenstone.  It  is  however  to  be  observed  that  the  wheel 
should  be  made  first  to  revolve  in  the  one  direction,  and  then  hi  the  opposite, 
that  the  marks  of  the  hacking-knife  may  cross  each  other. 

2. Smaller  and  harder  stones  are  more  commonly  polished  on  a  pewter  than  a 

lead  lap,  and  for  the  smallest  and  hardest  stones  a  copper  lap  is  preferred  ; 
but  all  the  polishing  tools,  of  what  metal  soever  they  may  be  made,  are 
hacked  as  above  described,  and  used  with  rottenstone  and  water. 

3. — ROUNDED  OR  CONVEX  STONES,  or  those  said  to  be  cut  en  cabochon,  whether  of 
Carnelian  or  even  several  of  the  harder  stones,  are  in  many  cases  succes- 
sively wrought  by  means  of  the  wood  mill  with  fine  emery,  the  list  mill  with 
pumice-stone,  and  leather  lap  with  putty  powder,  precisely  as  described  under 
the  head  Alabaster.  This  is  done  on  account  of  the  greater  elasticity  of  these 
apparatus,  which  enables  them  to  ply  more  conveniently  to  the  globular  forms 
of  the  works  to  be  polished,  and  avoid  wearing  them  in  ridges  or  flat  places. 

4.— FACETTED  WORKS  on  all  stones  and  hard  substances,  are  for  the  most  part  cut 
by  the  Lapidary  after  one  of  three  different  modes.  First,  for  pastes  or  arti- 
ficial stones,  and  many  soft  stones,  as  amber,  carnelian,  jet,  &c.,  the  facets 
are  usually  cut  on  a  lead  wheel  with  emery,  and  polished  on  pewter  with 
rottenstone. — Secondly,  for  some  of  a  harder  kind  but  inferior  in  hardness  to 
sapphires,  the  succession  of  tools  is  a  pewter  lap  and  fine  emery  for  the  cut- 
ting, and  a  copper  lap  with  rottenstone  for  the  polishing. — Thirdly,  for 
sapphires,  the  chrysoberyl,  and  rarely  for  some  few  others  likewise,  a  copper 
lap  with  diamond  powder  is  used  for  cutting  the  facets,  and  a  copper  lap 
with  rottenstone  for  polishing  them. — And  fourthly,  with  the  diamond,  two 
stones  are  rubbed  in  a  peculiar  manner  the  one  against  the  other  to  cut  the 
facets,  and  they  are  polished  by  means  of  the  dop,  and  an  iron  lap  or  skive 
fed  with  diamond  powder  ;  this  process  is  more  fully  described  in  vol.  1, 
page  176. 

5. — From  the  comparatively  small  size  of  the  stones  and  gems  that  are  cut  into 
facets,  they  cannot  generally  be  held  unassistedly  in  the  fingers,  the  stone  is 
consequently  cemented  centrally  upon  the  end  of  a  round  stick  of  wood, 
nearly  like  a  drawing  pencil.  The  stick  when  held  vertically)  gives  the  posi- 
tion for  grinding  the  central  facet  or  table  of  the  stone,  the  stick  is  inclined 
to  a  certain  angle  for  the  eight,  twelve,  or  more  facets,  contiguous  to  the 
table  ;  of  which  facets,  two,  three,  or  four  series  are  commonly  required  at 
different  inclinations,  and,  lastly,  the  horizontal  position  of  the  stick  serves  in 
cutting  the  girdle  or  central  band  around  the  exterior  edge  of  the  stones. 

The  several  inclinations  of  the  stick  on  which  the  stone  is  cemented,  are 
easily  determined  by  placing  the  upper  end  of  the  stick  into  one  of  several 
holes  in  a  vertical  post,  fixed  alongside  the  lap,  and  this  retains  the  inclina- 
tion very  accurately  and  simply,  but  all  these  matters  will  be  further  eluci- 
dated in  the  34th  chapter  on  Lapidary  Work  generally. 

6. — The  following  substances  are  worked  by  the  lapidary  in  nearly  or  exactly 
the  same  manner  as  carnelian,  and  descriptive  articles  are  introduced  hi 
the  catalogue  upon  each  of  these  particular  substances,  pointing  out  their 


AND    PROCESSES    FOR    GRINDING    AND    POLISHING. 


1046 


Agate 

Elvans 

Amethyst 

Emerald 

Aquamarine 

Felspar 

Beryl 

Flint 

Bloodstone                             Fluor  Spar 

Brazilian  Topaz                     Garnet 

Carbuncle                               Granite 

Cat's-eye 

Heliotrope 

Chalcedony 

Jade 

Chrysolite 

Jasper 

Chrysoprase 

Lapis  Lazuli 

Crystal 

Marble 

principal  external  features,  and  also  any  peculiarities  of  method,  pursued 
either  by  the  lapidary  or  other  artizan,  as  the  case  may  be,  in  working 
them. 

(SUBSTANCES  TREATED  BY  THE  LAPIDARY  LIKE  CARNELIAN.) 

Mina  Nova 

Onyx 

Opal 

Pastes 

Peridot 

Plasma 

Porphyry 

Quartz 

Sard 

Sardonyx 

Serpentine 

Topazes. 

CAST-IRON. — When  the  parts  of  machinery  that  are  made  in  cast-iron  are 
polished  they  are  treated  as  described  in  this  catalogue  under  the  general 
article  on  MACHINERY  made  of  iron  and  steel. 

THE  FRONT  OF  STOVES,  and  similar  bright  works  in  cast  iron;  are  first  ground 
on  large  grindstones,  and  then  buffed  on  large  revolving  buffs  upon  which 
a  coating  of  emery  has  been  fixed  by  glue.  They  are  sometimes  finished  by  a 
hand  rubber  used  as  a  spokeshave  having  a  piece  of  leather  supplied  with  fine 
emery  and  oil,  but  the  rubbers  suspended  from  the  ceiling  at  the  end  of  a 
powerful  spring,  are  also  very  judiciously  employed  in  these  large  works. 
See  the  end  of  the  article  BURNISHER. 

FIRE  IRONS  are  often  cast  in  iron  that  is  afterwards  rendered  malleable ;  which  is  a 
rapid  way  of  producing  beautiful  form,  combined  with  strength  and  a  certain 
measure  of  flexibility,  see  vol.  1,  page  259,  the  works  are  afterwards  case- 
hardened,  that  they  may  admit  of  a  better  lustre,  and  which  is  generally 
given  by  grindstones,  glazers,  buffs  and  brushwheels,  much  the  same  as  in 
cutlery  but  on  a  larger  scale. 

CAT'S-EYE,  a  mineral  consisting  of  quartz  enclosing  amianthus  or  asbestos,  and 
thence  possessing  the  property  emphatically  described  by  the  French  as 
chatoyant ;  the  cat's-eye  is  polished  just  like  AGATE  or  CARNELIAN. 

CHALCEDONY,  a  name  applied  to  many  siliceous  minerals  including  as  varieties 
the  onyx,  sard,  sardonyx,  plasma,  heliotrope,  and  chrysoprase  :  they  are 
wrought  like  CARNELIAN,  which  see. 


CHALK  when  simply  scraped,  or  else  crushed  under  the  hammer,  is  occasionally 
used  in  polishing  bone,  ivory,  and  some  few  soft  substances,  it  cuts  much 


1047       DESCRIPTIVE    CATALOGUE    OF    APPARATUS,    MATERIALS, 

more  quickly  in  its  natural  state  as  above,  than  when  manufactured  into  the 
well  known  article  Whiting. 

2. — WHITING  is  made  by  grinding  the  chalk  under  a  runner,  washing  it  for  the 
removal  of  sand  and  other  impurities,  sometimes  met  with  in  chalk,  and 
then  drying  it  in  lumps.  In  the  prepared  state  the  particles  of  the  chalk 
are  so  smooth,  as  hardly  to  abrade  any  but  very  soft  materials,  therefore 
the  principal  use  of  whiting  when  applied  to  the  metals  seems  to  be  the 
absorption  of  the  grease,  from  works  previously  polished  by  other  means. 

3. — CHALK  PREPARED  BY  DOUBLE  DECOMPOSITION. — A  recent  mode  of  preparing 
this  polishing  material,  so  as  to  obtain  it  perfectly  free  from  silex,  (which 
sometimes  accompanies  the  ordinary  kind  and  is  a  very  active  polishing 
material,)  is  as  follows.  Mix  filtered  and  transparent  solutions  of  the 
muriate  of  lime,  and  the  carbonate  of  soda,  when  these  are  thrown  in 
contact,  the  muriatic  acid  quits  the  lime  and  combines  with  the  soda, 
making  common  table  salt,  and  the  carbonic  acid  and  lime  unite  and  fall 
down  as  an  impalpable  precipitate,  which  may  be  collected  by  filtration.  The 
pure  carbonate  of  lime  thus  prepared,  polishes  quickly  and  smoothly,  and 
nevertheless  wears  away  the  material  so  little  as  not  in  any  perceptible 
degree  to  injure  its  form  or  sharpness,  it  seems  rather  to  burnish  than 
abrade  the  work. 

CHARCOAL. — Sticks  of  this  material  are  very  extensively  used  for  polishing 
several  of  the  metals,  and  the  action  seems  to  depend  on  the  silex  dissemi- 
nated throughout  the  substance  of  the  charcoal.  Considerable  discrimina- 
tion is  required  in  the  selection  of  pieces,  from  the  bulk  of  that  which  is 
prepared  from  small  green  wood  for  metallurgical  and  domestic  purposes, 
as  but  few  pieces  possess  the  requisite  cutting  quality  ;  the  workmen  gene- 
rally try  it  either  on  the  teeth  or  finger  nail. 

The  stick  of  charcoal  is  applied  at  an  angle  of  about  40  or  50  degrees  to 
the  work,  the  position  best  suited  to  every  piece  being  found  by  trial.  Some 
pieces  will  cut  rapidly  and  coarsely  with  water,  others  more  slowly  and 
smoothly  with  oil  ;  and  pieces  of  good  quality  are  very  highly  prized  by 
workmen.  Some  artizans  conceive  that  charcoal  cuts  more  greedily  when 
moistened  with  vinegar,  but  which  fluid  is  objectionable  as  it  stains  the 
metals. 

In  the  course  of  polishing,  the  charcoal  picks  up  the  abraded  particles  of 
metal,  they  sometimes  enter  its  pores,  and  would  scratch  the  work  if  allowed 
to  remain  on  the  charcoal,  consequently  two  pieces  are  mostly  used  ;  the 
one  merely  to  clean  the  other  by  rubbing  them  together  at  their  ends  in  the 
same  manner  that  the  painter  rubs  two  lumps  of  pumice-stone  together  to 
clean  their  surfaces.  In  finishing  delicate  works,  and  laying  the  grain, 
abundance  of  oil  or  water  should  be  used,  so  as  to  float  off  the  minute 
particles  of  metal  removed  in  the  process. 

The  charcoal  prepared  from  the  wood  of  elder  appears  to  have  the  decided 
preference  especially  for  polishing  the  steel  and  copper  plates  used  by 


AND    PROCESSES    FOR    GRINDING    AND   POLISHING.  1048 

engravers,  both  in  their  first  preparation,  and  in  the  removal  of  the  burrs 
thrown  up  by  the  graver.  To  ensure  the  possession  of  the  true  sort,  it  is 
recommended  to  obtain  the  waste  pieces  of  elder  from  the  rule  maker,  to  cut 
them  into  short  pieces,  and  then  to  burn  them  in  a  crucible  filled  with  sand, 
in  order  to  exclude  the  air,  otherwise  the  entire  substance  of  the  wood  may 
be  burned  to  ashes;  the  kitchen  or  forge  fire  may  be  used,  and  the  crucible 
should  be  allowed  to  cool  in  the  embers. 

The  charcoal  made  from  willow  truncheons,  is  described  as  being  much  in 
esteem  by  the  manufacturers  of  copper  plates  for  engravers  ;  and  elm  wood 
is  also  stated  by  Mr.  Thomas  Gill  as  being  suitable  for  making  the  charcoal 
for  polishing.  See  Tech.  Repos.  vol.  ii.  p.  264. 

[ARNLEY  FOREST  STONE,  See  HONE  SLATES,  article  2. 

[RYSOBERYL,  a  hard  aluminous  stone,  of  a  green  colour,  and  semi-trans- 
parent ;  it  is  chiefly  procured  in  Brazil,  and  is  worked  like  the  SAPPHIRE. 

[RYSOLITE  or  PERIDOT,  a  yellow  gem,  sometimes  tinged  with  green  or 
brown,  that  is  obtained  principally  from  the  Levant.  It  possesses  a  pecu- 
liarity, inasmuch  as  although  it  is  slit  and  facetted  just  like  Carnelian,  it 
can  scarcely  be  well  polished,  otherwise  than  by  means  of  a  copper  lap 
with  rottenstone,  a  few  drops  of  sulphuric  acid  being  used  instead  of  water 

to  moisten  the  rottenstone. 

• 

CHRYSOPRASE,  a  variety  of  CHALCEDONY,  of  an  apple  green  colour,  and  semi- 
opaque,  which  is  much  prized  by  jewellers.  It  is  cut  and  polished  after 
the  mode  of  Carnelian,  and  frequently  of  a  convex  form,  or  en  cdbochon. 

CLAY,  see  LOAM. 

CLOTH  is  extensively  used  as  a  vehicle  for  polishing  powders  of  all  kinds  ;  woollen 
and  felted  cloths  are  the  most  in  requisition.  Some  of  the  felted  cloths 
used  for  marble,  glass,  &c.,  and  which  are  called  nap,  are  upwards  of  half 
an  inch  thick.  Thinner  cloths,  such  as  the  stout  cloths  used  for  great  coats 
and  for  the  blankets  of  printing  presses,  are  also  employed,  especially  when 
discarded  from  their  original  purposes,  and  also  ordinary  woollen  cloth, 
including  the  list,  or  selvedges,  and  so  on. 

Old  worsted  stockings  are  used  hi  many  trades  ;  linen  and  cotton  cloths 
and  rags  are  also  employed,  but,  from  being  thinner,  are  less  generally  used 
than  woollen  cloths. 
CLOTH  WHEELS,  see  Wheels,  articles  61  to  64. 

)LCOTHAR  OF  VITRIOL,  see  OXIDE  OF  IRON. 

>NES.— The  principal  modes  of  grinding  cones  will  be  explained  in  Chap. 
XXXIII.,  Sect.  3. 


1049         DESCRIPTIVE    CATALOGUE    OF    APPARATUS,    MATERIALS, 

COPPERSMITH'S  WORK,  subsequently  to  its  having  been  annealed  for  the  last 
tune,  and  before  it  is  planished  with  the  hammer,  is  generally  pickled  with 
sulphuric  acid  and  water,  in  about  equal  parts,  and  scoured  with  coarse  red 
tripoli  and  water,  to  remove  the  oxidation  caused  by  the  fire.  The  work 
when  planished  is  cleaned,  1st,  with  crocus  and  oil,  2ndly,  the  oil  is  rubbed 
off  with  whiting,  and  3rdly,  the  work  is  polished  with  dry  crocus,  the 
rubber  being  generally  an  old  worsted  stocking. 

COQUILLA  NUT  receives  a  good  natural  polish  by  the  following  applications  : — 
1st,  glass  paper  ;  2ndly,  tripoli  and  oil  on  rag ;  3rdly,  dry  putty  powder  or 
rottenstone.  This  routine  gives  a  more  durable  polish  than  hardwood 
lacker  applied  with  friction,  a  mode  of  finish  also  employed. 

Common  turned  and  filed  works  are  often  finished  with  one  or  two  coats  of 
varnish,  applied  like  paint  with  a  brush,  this  gives  them  a  coarse  brightness. 

Eccentric  turned  works  hi  coquilla  nut  are  polished  very  slightly  with 
putty  powder  or  rottenstone  and  oil  on  a  brush  ;  but  the  tools  should  be  very 
sharp,  so  as  to  leave  but  little  or  no  necessity  for  polishing  at  ah1. 

CORAL. — The  red  variety  of  this  singular  substance  is  somewhat  used  hi  jewellery, 
and  admits  of  an  excellent  polish.  When  hi  rounded  pieces,  it  is  polished 
after  the  routine  followed  by  the  lapidary  with  ALABASTER  ;  when  coral  is  cut 
in  facets  as  for  beads,  &c.,  it  is  worked  like  CARNELIAN. 

COROSOS  or  the  vegetable  ivory  nut,  see  vol.  1,  page  112,  is  polished  just  the  same 
as  the  ivory  of  the  elephant,  and  other  animals ;  but  the  vegetable  ivory, 
apparently  from  its  facility  of  absorbing  moisture,  alters  sensibly  in  size  and 
form  during  the  process  of  polishing. 

CORUNDUM  includes  very  dissimilar  minerals,  all  consisting  almost  entirely  of 
highly  crystalline  alumina,  namely, — Precious  Corundum,  or  the  Sapphire 
and  Ruby, — Common  Corundum — and  Emery. — The  last  two  are  the  common 
abrasives  of  the  Asiatics  and  Europeans  respectively ;  and  all  are  separately 
described  under  their  respective  heads  in  this  catalogue. 

1. — COMMON  CORUNDUM,  says  Phillips,  probably  from  its  texture,  has  received  the 
name  of  imperfect  Corundum  ;  and  from  its  hardness,  and  from  its  occasional 
pearly  lustre,  Adamantine  Spar :  it  occurs  everywhere  from  China  to 
Bengal,  and  is  met  with  of  various  colours,  but  more  often  of  a  greyish  or 
greenish  tint.  Corundum  is  much  used  in  India  for  Corundum  Wheels  and 
Rubbers,  the  methods  of  constructing  which  are  described  in  the  following 
articles  : — 

2.— CORUNDUM  WHEEL. — «  This  kind  of  lapidaries'  wheel  is  called  in  the  Tamul 
language  Couroundum-sane.  It  is  composed  of  corundum,  more  or  less 
finely  powdered,  cemented  together  by  lac-resin :  the  proportions,  by  volume, 
consisting  of  two-thirds  of  powdered  corundum,  and  one-third  of  lac-resin. 
The  corundum  powder  is  put  into  an  earthen  vessel,  and  heated  over  a  clear 


AND    PROCESSES    FOR    GRINDING    AND    POLISHING.  1050 

fire  ;  and  when  of  a  sufficient  heat,  (which  is  ascertained  by  a  small  piece  of 
the  resin  readily  fusing,)  the  resin  is  added  in  portions,  carefully  stirring  at 
the  tune,  to  form  an  intimate  mixture.  When  made  into  a  mass,  it  is  put 
upon  a  smooth  slab  of  stone,  and  kneaded  by  beating  it  with  a  pestle ;  it  is 
then  rolled  upon  a  stick,  reheated  several  times,  continually  kneading  it  until 
the  mixture  is  perfectly  uniform.  It  is  afterwards  separated  from  the  stick, 
laid  again  upon  a  stone  table  which  has  been  previously  covered  with  very  fine 
corundum  powder,  and  flattened  into  the  form  of  a  wheel  by  an  iron  rolling 
pin.  The  wheel  is  then  polished  by  a  plate  of  iron  and  corundum  powder  ; 
and  finally,  a  hole  is  made  through  the  middle  of  it  by  a  heated  rod  of  copper 
or  iron. 

"  These  wheels  are  made  with  a  grain  more  or  less  fine,  as  the  coarser 
perform  the  first  rough  work,  and  the  finer  cut  the  stones.  They  are 
mounted  on  a  horizontal  axis,  and  the  workman,  sitting  on  the  ground, 
makes  them  revolve  with  a  spring-bow,  which  he  moves  with  his  right  hand, 
at  the  same  time  holding  the  stone  with  his  left  against  the  wheel,  the  latter 
being,  from  time  to  time,  carefully  moistened  and  sprinkled  with  corundum 
powder.  The  polish  is  given  by  wheels  of  lead  and  very  fine  corundum 
powder." 

3. — CORUNDUM  RUBBERS. — "  The  proportions  generally  used  in  making  the  corun- 
dum rubbers  are,  for  the  coarse,  lac,  8,  corundum,  1  ;  for  the  medium, 
lac,  12  to  16,  and  corundum  1,  by  weight.  The  fine  rubber  is  made  by 
mixing  the  grindings  of  agates,  carnelians,  and  the  like,  with  lac  ;  and  as  the 
lapidary's  wheels,  upon  which  they  are  ground  are  made  of  corundum  and 
lac  also,  the  grindings  must  contain  a  portion  of  those  materials;  their  pro- 
portion, in  composition,  must  vary  according  to  the  nature  of  the  stone  from 
which  they  are  ground  ;  but  6  of  lac  to  1  of  grindings,  may  be  considered  a 
good  proportion  generally. 

"  The  lac  is  first  melted,  and  the  corundum,  after  it  has  been  reduced  to  a 
powder,  mixed  intimately  with  it.  The  composition  is  then  moulded  in  the 
shape  of  a  brick  about  6  x  4  X  H  inch,  with  a  handle  of  wood  about  6  inches 
at  one  end,  having  a  rise  of  about  30  degrees  for  the  convenience  of 
working  it." 

Some  dentists  employ  old  files  thinly  coated  with  a  cement  of  emery  and 
shell  lac,  in  finishing  the  enamel  or  mineral  teeth.  The  incorporation  of  the 
materials  is  greatly  assisted  when  the  emery  or  corundum  is  heated  to  the 
melting  point  of  the  gum  resin. 

"HOCUS.    See  OXIDE  OF  IRON. 

JRYSTAL,  or  ROCK  CRYSTAL,  is  a  popular  name  for  Quartz,  or  pure  crystalline 
silex,  the  finest  and  largest  crystals  of  which  are  found  in  Madagascar 
Dauphin^,  and  the  Alps ;  the  so  called  Bristol  diamonds  are  nothing  but  fine 
specimens  of  quartz  cut  and  polished. 

The  Brazilian  pebbles  for  spectacles  are  lenses  ground  out  of  pure,  trans- 


1051         DESCRIPTIVE    CATALOGUE    OF    APPARATUS,    MATERIALS,. 

parent,  colourless  quartz,  the  stone  is  cut  into  slices  by  the  lapidary,  after- 
wards it  is  snipped  into  the  form  of  the  lenses,  with  nippers  which  resemble 
wide  flat  pliers,  and  are  made  of  soft  iron,  in  order  that  the  quartz  or  glass  may 
slightly  imbed  itself,  to  gain  a  hold,  which  could  not  take  place  with  the  hard 
steel  faces  of  ordinary  pliers  ;  lastly  the  pieces  of  crystal  are  ground  into 
the  form  of  lenses  and  polished  by  the  optician,  exactly  in  the  same  mode 
that  he  employs  for  glass  lenses,  and  which  will  be  described. 

Many  remarkable  specimens  of  cups,  tazzas,  and  other  works  of  art  have 
been  formed  by  abrasion  from  the  beautiful  material  rock  crystal,  or  quartz  ; 
some  of  these  may  be  seen  in  the  British  Museum,  and  excite  astonishment 
by  the  laborious  perseverance  they  evince. 

CUTLER'S  GREEN  HONE,  see  HONE  SLATES,  article  6. 

CUTLERY  is  ground  and  polished  with  the  various  natural  and  artificial  grinders, 
the  constructions  and  applications  of  which  are  described  under  the  article 
WHEELS  in  this  Catalogue :  the  ordinary  succession  of  the  principal  processes 
will  be  therefore  alone  adverted  to  in  this  place. 

1. — FINE  CUTLERY. — The  manufacture  of  a  razor  blade  of  the  best  quality  may  be 
viewed  as  a  suitable  example  of  the  mode  of  treating  articles  of  fine  cutlery  : 
the  succession  of  processes  is  as  follows  :— 1st,  the  blade  is  moulded  ;  2ndly, 
forged  ;  3rdly,  ground  into  form  and  scorched,  or  the  black  scale  ground  off  : 
this  is  done  on  a  dry  coarse  Wickersley  grit  stone  ;  4thly,  the  blade  is 
drilled  for  the  joint  and  stamped  with  the  name  ;  5thly,  hardened  and  tem- 
pered (see  vol.  1,  page  248)  ;  Gthly,  ground  on  a  wet  Wickersley  grit  stone 
from  4  to  8  inches  diameter  ;  7thly,  the  shoulders  of  the  blade  are  sometimes 
ground  on  a  fine  dry  stone  ;  for  this  purpose  the  edge  of  the  stone  is  waxed 
up,  or  kept  keen  by  rubbing  bees-wax  on  the  side  near  the  periphery  to 
hold  the  particles  of  the  stone  together  ;  the  wax  keeps  the  stone  from 
crumbling  away,  but  the  dry  stone  should  be  sparingly  used  after  hardening, 
as  it  is  liable  to  soften  the  edge  of  the  blade  ;  8thly,  the  blade  is  lapped  on  a 
lead  lap  of  a  diameter  a  little  smaller  than  the  grindstone  employed  in  the 
6th  process — the  lap  scarcely  alters  in  course  of  use,  and  gives  the  true 
curve  to  the  surfaces  ;  9thly,  the  tang  and  back  are  glazed  on  a  leather 
glazer  ;  1  Othly,  the  razor  blade  is  polished  on  a  soft  buff  wheel  fed  with  dry 
crocus  and  revolving  very  slowly.  This  completes  the  manufacture  of  the 
blade,  which  is  then  ready  to  be  handled  preparatory  to  the  setting,  which 
will  be  described  in  Chapter  XXXII. 

The  best  penknife  blades  and  scissors  are  treated  in  a  similar  manner  to 
the  above. 

2. — COMMON  CUTLERY. — All  work  should  be  scorched  or  dry  ground  to  remove 
the  scale  before  hardening,  but  this  is  frequently  omitted  in  common  works, 
and  the  usual  routine  after  hardening  is,  1st,  the  coarse  wet  stone  ;  2ndly, 
the  fine  wet  stone  ;  and,  Srdly,  the  buff  with  fine  emery.  Sometimes  one  or 


AND    PROCESSES    FOR    GRINDING    AND    POLISHING.  1052 

more  intermediate  stages  between  the  extremes  of  the  common  and  best 
cutlery  are  resorted  to,  according  to  price.     Common  razors,  after  being 
hardened,  are,  1st,  ground  on  a  wet  stone  from  12  to  15  inches  diameter ; 
2ndly,  lapped  ;  and,  3rdly,  polished. 
3. — EDGE  TOOLS  are  treated  the  same  as  common  cutlery. 

DEVONSHIRE  OILSTONE,  see  HONE  SLATES. 

DIAMOND,  this  remarkable  and  most  useful  gem  has  been  considered  at  some 
length  in  the  first  volume,  pages  175 — 180 — first  as  regards  the  processes  of 
splitting,  cutting,  and  polishing  diamonds  for  jewellery, — then  its  use  in  the 
hands  of  the  glass-cutter  and  glazier — and  lastly  several  of  the  uses  of  the 
diamond  as  tools,  and  which  applications  include  the  formation  of  the 
jewelled  holes  of  ruby  and  sapphire  for  watches  and  chronometers,  every 
process  of  which  requires  the  intervention  of  the  diamond. 

In  this  place  it  is  proposed  to  describe  the  three  different  modes  in  which 
the  diamond  powder  is  prepared  for  the  use  of  various  artizans,  as  the 
subsequent  chapters  will  treat  of  its  practical  application  by  the  lapidary, 
gem-engraver,  and  others. 

1. — DIAMOND  POWDER  FOR  LAPIDARIES'  USE. — Lapidaries  generally  purchase  small 
imperfect  diamonds,  and  the  fragments  removed  by  splitting  or  cleavage,  in 
preparing  stones  for  jewellery.  These  fragments  are  crushed  in  a  hardened 
steel  mortar  with  a  cylindrical  hole  about  half  an  inch  diameter,  and  nearly 
two  inches  deep,  the  bottom  of  the  cavity  is  hemispherical  or  constitutes 
perhaps  the  third  part  only  of  the  circle,  the  pestle  almost  fits  the  aperture 
of  the  mortar  and  is  curved  to  the  same  degree,  there  is  also  a  cover  that  fits 
a  recess  in  the  mortar  to  prevent  the  escape  of  any  of  the  valuable  dust. 

The  pestle  is  struck  a  few  blows  with  a  light  hammer,  and  is  twisted 
round  between  each  blow,  this  readily  crushes  the  diamond,  which,  although 
so  incomparably  hard,  is  brittle  from  its  crystalline  structure.  The  frag- 
ments are  carefully  collected,  and  mixed  with  a  little  of  the  oil  of  brick,  in  a 
small  cup  or  any  convenient  vessel,  which  should  have  a  cover  to  keep  the 
prepared  diamond  from  being  wasted.  When  not  wanted  for  immediate  use, 
the  prepared  diamond  is  kept  in  a  pasty  condition  between  two  very  small 
watch  glasses,  cemented  with  soft  wax  around  their  edges. 

2. — DIAMOND  POWDER  FOR  SEAL  ENGRAVERS. — This  is  required  to  be  much  more 
finely  pulverized  than  for  lapidary  work,  therefore  having  been  crushed  as 
above,  the  fragments  are  ground  into  a  thick  paste,  with  a  few  drops  of 
olive  oil,  in  another  pestle  and  mortar  of  hardened  steel,  the  surfaces  of 
which  are  both  exactly  spherical  with  a  curvature  of  from  one  to  two  inches 
radius ;  this  mortar  has  a  tin  cover  that  it  may  serve  as  the  recipient  for  the 
powder  which  has  been  ground.  Sometimes  for  reducing  the  powder  after 
it  has  been  crushed,  flat  grinders  of  hardened  steel  are  employed,  but  these 
are  less  generally  used  than  the  spherical  form.  Rough  diamonds  of  a  dark 
steely  colour  are  generally  selected  by  the  seal  engravers,  as  these  are  con- 
sidered the  hardest  stones. 


1053        DESCRIPTIVE   CATALOGUE    OF    APPARATUS,    MATERIALS, 

3. — DIAMOND  POWDER  FOB  WATCH  JEWELLERS. — These  artizans  who  use 

larger  quantities  of  diamond  powder  than  the  above,  for  cutting  as  well  as  for 
polishing  rubies,  sapphires,  and  topazes,  pursue  a  different  method.  They 
purchase  the  fine  dust,  or  diamond  bort3  that  is  rubbed  off  stones  used  for 
jewellery  hi  the  act  of  cutting  them  into  facets,  in  which  process  two  dia- 
monds are  operated  upon  at  once,  and  caused  mutually  to  abrade  each  other 
in  forming  the  one  facet  on  each  stone  ;  see  vol.  1,  page  176.  The  diamond 
bort  is  usually  washed  for  its  separation  into  two  or  three  sizes,  exactly  after 
the  manner  of  washing  emery,  except  that  the  process  is  carried  on  upon  a 
very  much  smaller  scale,  and  the  finest  olive  oil  is  used  instead  of  water,  the 
diamond  powder  is  generally  laid  by  under  a  stratum  of  oil  to  prevent  waste ; 
oil  is  employed  because  of  its  viscidity,  it  does  not  allow  the  diamond  to  sub- 
side so  quickly  as  water,  and  it  is  moreover  the  fluid  always  employed  in  the 
using  and  preservation  of  the  diamond  by  these  artizans. 

4. — THE  APPLICATION  OF  DIAMOND  POWDER  to  the  splitting  or  sawing  of  minerals 
will  be  described  in  the  chapter  XXXIV.  on  Lapidary  work.  The  coarser 
diamond  powder  used  for  grinding  or  cutting  is  generally  burnished  into  the 
surface  of  the  iron  lap  or  skive  of  the  diamond  worker,  and  frequently  also 
into  the  iron,  copper,  or  other  laps  used  by  different  artizans  :  hi  cutting 
sapphires  the  lapidary  works  the  diamond  powder  into  the  copper  lap,  with  a 
smooth  piece  of  agate  applied  with  gentle  pressure.  The  finer  diamond  powder 
used  for  polishing,  is  simply  applied  on  the  surface  of  the  tools,  with  the 
finger,  or  a  small  flattened  wire  used  as  a  spatula.  The  gem  engraver  puts 
the  diamond  hi  minute  hollowed  disks  of  tin,  two  of  which  hi  fact  are  soldered 
to  a  strip  of  tin,  and  worn  on  the  forefinger  of  the  left  hand  as  a  ring :  the  one 
disk,  of  half  an  inch  diameter,  contains  the  mixed  diamond  paste,  the  other 
disk,  one  or  two  drops  of  the  oil  of  brick,  with  which  the  tool  is  frequently 
lubricated. 

5. — FICTITIOUS  DIAMONDS. — The  white  sapphire  is  sometimes  used  hi  jewellery  as 
a  substitute  for  the  diamond,  and  the  zircon  is  said  also  to  be  so  employed 
when  deprived  of  its  colour  by  heat :  the  so-called  Bristol  diamonds  are 
crystals  of  quartz  cut  and  polished,  but  those  imitations  which  are  con- 
sidered to  come  the  nearest  to  real  diamonds,  in  point  of  lustre  or  colour, 
though  not  in  hardness,  are  met  with  amongst  the  pastes  of  the  first  quality, 
which  are  made  artificially,  and  polished  on  pewter  wheels  with  rottenstone, 
and  not  on  copper  wheels,  like  most  of  the  hard  gems. 

DUTCH  RUSH,  or  the  Equisetum  Hyemale,  is  said  to  be  a  native  of  Scotland,  and 
to  thrive  best  in  the  marshy  places  in  mountainous  districts  ;  it  is  gathered 
in  pieces  two  or  three  feet  long,  which  are  intersected  by  knots  at  distances 
of  four  to  six  niches.  The  rush  is  usually  of  the  size  of  a  writing  quill,  of 
a  greenish-grey  colour,  with  a  groovy  surface  that  feels  rough  like  fine  glass 
paper,  from  the  quantity  of  silex  disseminated  throughout  its  exterior 
surface,  and  upon  which  circumstance  depends  its  suitability  to  polishing 
hardwoods,  alabaster,  marbles,  and  some  other  substances.  According  to 


AND    PROCESSES    FOR    GRINDING    AND    POLISHING.  1054 

the  analysis  of  Sprengel,  Dutch  Rush,  wheii  dry,  contains  rather  more  than 
13  per  cent,  of  ashes,  viz.  Silex,  6-38,  Garb.  Lime,  5-51,  Potash  salts,  -79,  and 
Alumina  -46. 

For  the  application  of  Dutch  Rush,  see  WOOD,  article  5,  and  ALABASTER, 
article  1. 

EDGE  TOOLS  are  treated  of  under  the  head  CUTLERY. 

ELECTRUM  or  GERMAN  SILVER. — See  Silver,  Albata,  and  Brass.  The  respective 
modes  being  used,  according  to  the  nature  of  the  works  made  in  this  triple 
alloy,  which  differs  greatly  as  to  value  and  quality. 

ELVANS,  the  modes  of  working  and  polishing  porphyry  and  granite,  and  also  the 
elvans,  which  are  of  intermediate  character  between  these  two,  are  described 
in  pages  169  to  172  of  the  first  volume.  By  the  lapidary,  the  elvans  and 
porphyries  are  wrought  like  CARNELIAN,  the  granite  somewhat  differently,  on 
account  of  its  unequal  hardness,  see  GRANITE. 

EMERY. 

1. — ORDINARY  PREPARATION  OF  EMERY. — The  following  is  the  manufacturers' 
ordinary  process  ;  the  lumps  of  emery  stone  are  broken  up  precisely  after 
the  manner  of  stone  for  repairing  Macadamized  roads,  and  into  lumps  of 
similar  size.  The  lumps  are  then  crushed  under  stampers  such  as  are  used  for 
pounding  metallic  ores,  and  driven  by  water  or  steam  power  ;  the  stampers 
are  considered  to  leave  the  particles  more  angular  than  they  would  be  if 
ground  under  runners,  a  mode  sometimes  employed.  The  coarse  powder  is 
then  sifted  through  sieves  of  wire  cloth,  which  are  generally  cylindrical,  like 
the  bolting  cylinders  of  corn  mills,  but  the  sieves  are  covered  with  wire 
cloth,  having  in  general  about  90  to  16  wires  to  the  inch.  The  following 
table  shows  the  numbers  of  wires  usually  contained  in  the  sieves,  and  the 
names  of  the  kinds  respectively  produced  by  them  : — 


16.  Corn  emery. 

24.  Coarse  grinding 

36.  Grinding 

46.  Fine  grinding 


60.  Coarse     flour    emery 
70.  Flour 

80.  Fine  flour         

90.  Superfine  flour 


53.  Super  grinding  

No.  16  sieve  gives  emery  of  about  the  size  of  mustard  seed,  and  coarser 
fragments  extending  nearly  to  the  size  of  peppercorns,  are  also  occasionally 
prepared  for  the  use  of  engineers. 

The  sieves  have  sometimes  as  many  as  120  wires  in  the  inch,  the  very  fine 
sizes  of  emery  are  however  more  commonly  sifted  through  lawn  sieves;  but 
the  finest  emery  that  is  obtained  from  the  manufacturers,  is  that  which  floats 
in  the  atmosphere  of  the  stamping  room,  and  is  deposited  on  the  beams  and 
shelves,  from  which  it  is  occasionally  collected. 

The  manufacturers  rarely  or  never  wash  the  emery,  which  is  mostly  done 


1055        DESCRIPTIVE    CATALOGUE    OF    APPARATUS,    MATERIALS, 

by  the  glass  workers,  opticians,  and  such  others  as  require  a  greater  d( 
of  precision  than  can  be  obtained  by  sifting. 
2. — WASHING  EMERY  BY  HAND. — Washing-over  or  elutriation,  as  the  process  is 
called  by  chemists,  is  a  valuable  application  of  the  law  of  gravity  to  the 
chemical,  metallurgical  and  mechanical  arts.  Thus  the  alluvial  deposits  of 
some  of  the  tropical  rivers  are  washed  for  the  separation  of  the  particles  of 
gold  they  contain.  A  small  portion  of  the  mud  of  the  river  is  stirred  in  a 
large  quantity  of  water  contained  in  a  broad  shallow  basin,  the  gold  being 
several  times  as  heavy  as  the  earthy  particles  quickly  subsides,  and  the  mud 
which  remains  suspended  for  a  long  period  in  the  water,  is  removed  by  pour- 
ing off  the  water  from  the  valuable  sediment. 

In  a  similar  manner  the  particles  of  emery  and  other  powders  may  be 
separated  according  to  their  magnitudes,  in  a  more  accurate  manner  than  can 
be  accomplished  by  sieves.  A  portion  of  emery,  powder  of  uncertain  size  is 
thoroughly  well  mixed  in  a  large  quantity  of  water,  as  in  a  common  wash 
hand  basin,  and  at  the  end  of  1 0  seconds  the  liquid  is  poured  off  from  the 
sediment  which  has  fallen  down  in  that  period  ;  the  sediment  is  laid  aside  in 
a  separate  vessel.  The  bulk  is  again  stirred  and  poured  off  at  1 0  seconds, 
and  this  second  sediment  added  to  the  first,  and  which  process  is  repeated 
until  no  further  sediment  is  deposited  in  the  period  of  10  seconds ;  the  process 
requires  watchfulness  and  a  steady  hand.  A  fresh  deposit  is  similarly  collected 
from  the  residue  after  a  longer  period  of  rest,  say  20  seconds,  until  the  whole 
quantity  of  emery  is  divided  into  grains  of  so  many  sizes,  as  may  be  required 
for  the  particular  branch  of  manufacture  for  which  it  is  intended ;  thus — 
3. — EMERY  FOR  THE  CONSTRUCTION  OF  MECHANISM. — The  author  has  been  for 
many  years  in  the  habit  of  employing  emery  of  twelve  degrees  of  fineness, 
part  of  them  prepared  by  himself  by  washing  over,  namely  : 
No.  1.  Corn  emery  of  commerce  prepared  by  sifting 

„    2.  Grinding  „ 

„    3.  Fine  grinding  „ 

,,4.  Superfine  grinding  „ 

„    5.  Deposited  at  the  end  of  2  seconds, 

»     6'  n  5          » 

»    7.  „  10        „ 

„    8.  „  20        „ 

„    9.  „  60        „ 

„  10.  „  3  minutes. 

,,H.  „  15        „ 

,,12.  „  60        „ 

The  emeries  of  the  sizes  5  to  12  are  preserved  in  glass  bottles,  to  prevent 
them  from  becoming  accidentally  mixed  or  contaminated  with  foreign 
substances. 

4. — EMERY  FOR  OPTICAL  PURPOSES. — Mr.  Ross  mixes  four  pounds  of  the  flour 
emery  of  commerce,  with  1  ounce  of  powdered  gum  arable,  and  then  throws 
the  powder  into  2  gallons  of  clean  water.  He  collects  deposits,  as  above 


AND    PROCESSES    FOR    GRINDING    AND    POLISHING.  1056 

described,  at  the  end  of  10  seconds,  30  seconds,  2  minutes,  10,  20,  and  60 
minutes,  and  that  which  is  not  deposited  by  one  hour's  subsidence  is  thrown 
away  as  useless  for  grinding  lenses.  The  use  of  the  gum  arable,  which 
renders  the  water  slightly  viscid,  was  recommended  by  Dr.  Green  for  pre- 
paring red  oxide  of  iron,  for  polishing  specula.  See  Trans.  Soc.  of  Arts. 
Vol.  L.  p.  152. 

5. — WASHING  EMERY  IN  THE  LARGE  WAY. — Washing  emery  by  hand  as  above 
explained  is  far  too  tedious  for  those  who  require  very  large  quantities  of 
emery,  ssuch  as  the  manufacturers  of  plate  glass  and  some  others,  who 
generally  adopt  the  following  mode  : — Twelve  or  more  cylinders  of  sneet 
copper,  of  the  common  height  of  about  two  feet,  and  varying  from  about  3, 5, 
8  to  30  or  40  inches  in  diameter,  are  placed  exactly  level,  and  communicating 
at  their  upper  edges,  each  to  the  next,  by  small  troughs  or  channels  ;  the 
largest  vessel  has  also  a  waste  pipe  near  the  top. 

At  the  commencement  of  the  process,  the  cylinders  are  all  filled  to  the 
brim  with  clean  water,  the  pulverised  emery  is  then  churned  up,  with 
abundance  of  water  in  another  vessel,  and  allowed  to  run  into  the  smallest  or 
the  three  inch  cylinder,  through  a  tube  opposite  the  gutter  leading  to  the 
second  cylinder.  The  water,  during  its  short  passage  across  the  three  inch 
cylinder,  deposits  hi  that  vessel,  such  of  the  coarsest  emery  as  will  not  bear 
suspension  for  that  limited  time  ;  the  particles  next  finer,  are  deposited  hi 
the  second  or  the  five  inch  cylinder,  during  the  somewhat  longer  time  the 
mixed  stream  takes  in  passing  the  brim  of  that  vessel  and  so  on.  Eventually 
the  water  forms  a  very  languid  eddy  in  the  largest  cylinder,  and  deposits 
therein  the  very  fine  particles  that  have  remained  in  suspension  until  this 
period,  and  the  water  lastly  escapes  by  the  waste  pipe  nearly  or  entirely  free 
from  emery. 

In  this  simple  yet  elegant  arrangement,  time  is  also  the  measure  of  the 
particles  respectively  deposited  hi  tthe  12  or  more  vessels,  their  number 
being  determined  by  the  quantity  of  sizes  respectively  required  hi  the  manu- 
facture to  which  the  emery  is  applied.  When  the  vessels  are  to  a  certain 
degree  filled  with  emery,  the  process  is  stopped,  they  are  emptied,  the  emery 
is  carefully  dried  and  laid  by,  and  the  process  is  recommenced. 
6. — EMERY  PAPER  is  prepared  like  glass  paper,  and  of  about  six  degrees  of 
coarseness.  The  powders  sifted  through  the  sieves  with  30  and  90  meshes 
per  linear  inch  being  in  general  the  coarsest  and  finest  sizes  employed.  When 
used  by  artizans,  the  emery  paper  is  commonly  wrapped  around  a  file  or  a 
slip  of  wood,  and  applied  just  like  a  file,  with  or  without  oil,  according  to 
circumstances.  The  emery  paper  cuts  more  smoothly  with  oil,  but  leaves 
the  work  dull. 

7. — EMERY  CLOTH  only  differs  from  emery  paper  in  the  employment  of  thin 
cotton  cloth  instead  of  paper,  as  the  material  upon  which  the  emery  is  fixed 
by  means  of  glue.  The  emery  cloth,  when  folded  around  a  file,  does  not  ply 
so  readily  to  it  as  emery  paper,  and  is  apt  to  unroll,  therefore  smiths, 
engineers  and  others,  give  the  preference  to  the  emery  paper  and  emery 


1057        DESCRIPTIVE    CATALOGUE    OF    APPARATUS,    MATERIALS, 

sticks  ;  but  for  household  and  other  purposes,  where  the  hand  alone  is  used, 
the  greater  durability  of  the  cloth  is  advantageous.  Edwards'  patent  for 
emery  cloth  was  taken  out  in  December  1 830. 

8. — EMERY  STICKS,  are  rods  of  deal  about  8  to  12  inches  long,  planed  up  square, 
or  with  one  side  rounded  like  the  half  round  file.  Nails  are  driven  into  each 
end  of  the  sticks  as  temporary  handles,  they  are  then  brushed  over  one  at  a 
time,  with  thin  glue,  and  dabbed  at  all  parts  in  a  heap  of  emery  powder,  and 
knocked  on  one  end  to  shake  of  the  excess,  two  coats  of  glue  and  emery  are 
generally  used.  The  emery  sticks  are  much  more  economical  than  emery 
paper  wrapped  on  a  file,  which  is  liable  to  be  torn. 

9. — EMERY  CAKE  consists  of  emery  mixed  with  a  little  suet  chopped  small,  rendered 
down,  and  mixed  with  a  very  little  bees'  wax,  so  as  to  constitute  a  solid  lump, 
with  which  to  dress  the  edges  of  buff  and  glaze  wheels.  The  ingredients 
should  be  thoroughly  incorporated  by  stirring  the  mixture  whilst  fluid,  after 
which  it  is  frequently  poured  into  water,  and  thoroughly  kneaded  with  the 
hands,  and  rolled  into  lumps  before  it  has  time  to  cool.  The  emery  cake  is 
sometimes  applied  to  the  wheels  whilst  they  are  revolving ;  but  the  more 
usual  course  is  to  stop  the  wheel,  and  rub  in  the  emery  cake  by  hand,  it  is 
afterwards  smoothed  down  with  the  thumb. 

10. — EMERY  PAPER,  OR  EDWARDS'  PATENT  RAZOR  STROP  PAPER,  is  a  new  article 
in  which  fine  emery  and  glass  are  mixed  with  the  paper  pulp,  and  made  into 
sheets  as  in  making  ordinary  paper.  The  emery  and  glass  are  said  to  con- 
stitute together  60  per  cent,  of  the  weight  of  the  paper,  which  resembles 
drawing  paper  except  that  it  has  a  delicate  fawn  colour.  This  emery  paper 
is  directed  to  be  pasted  or  glued  upon  a  piece  of  wood,  and  when  rubbed  with 
a  little  oil  to  be  used  as  a  razor  strop,  of  which  it  is  by  far  the  least  expensive 
of  any  previously  in  use.  The  patent  for  this  invention  was  granted  to  the 
Rev.  Mr  Edwards,  in  November  1843,  and  he  was  rewarded  for  the  same  by 
the  Society  of  Arts,  in  June,  1846. 

11. — BARCLAY'S  ARTIFICIAL  EMERY  STONE. — The  numerous  articles  already  given 
on  emery,  and  various  ways  in  which  it  is  prepared  and  used  will  be  concluded 
by  a  description  of  the  invention  of  a  Mr.  Henry  Barclay,  who  took  out 
letters  patent  in  August,  1842,  for  a  very  efficient  mode  of  combining  powdered 
emery  into  disks  and  laps  of  different  kinds,  suitable  to  grinding,  cutting, 
and  polishing  glass,  enamels,  metals,  and  other  hard  substances.  The  process 
of  manufacture  is  as  follows  : — 

Coarse  Emery  Powder  is  mixed  with  about  half  its  weight  of  pulverized 
Stem-bridge  loam,  and  a  little  water  or  other  liquid,  to  make  a  thick  paste, 
this  is  pressed  into  a  metallic  mould  by  means  of  a  screw  press,  and  after 
having  been  thoroughly  dried,  is  baked  or  burned  in  a  crucible,  muffle,  or  close 
receiver,  within  a  furnace,  at  a  temperature  considerably  above  a  "  red  heat," 
and  below  the  "full  white  heat." 

In  this  case  the  clay  or  alumine  serves  as  a  bond,  and  unites  the  particles 
very  completely  in  a  solid  substance,  called  A rtificial  Emery  Stone,  which  cuts 
very  greedily,  and  yet  seems  hardly  to  suffer  perceptible  wear  or  destruction. 


AND    PROCESSES    FOR    GRINDING    AND    POLISHING.  1058 

Superfine  Grinding  Emery,  is  formed  into  wheels  exactly  in  the  same  manner 
as  the  above,  but  the  proportion  of  loam  is  then  only  one-fourth,  instead  of 
one-half  that  of  the  emery  :  these  emery  stones,  which  are  of  medium  fine- 
ness, cut  less  quickly  but  more  smoothly  than  the  above. 

Flour  Emery,  when  manufactured  into  artificial  stones,  requires  no  uniting 
substance,  but  the  moistened  flour  emery  is  alone  forced  into  the  metal 
mould  and  fired,  as  some  portions  of  the  alumine  present  seem  abundantly 
to  suffice  to  unite  the  remainder.  These  fine  wheels  render  the  works  sub- 
mitted to  them  exceedingly  smooth,  but  they  do  not  produce  a  high  polish  on 
account  of  the  comparative  coarseness  of  the  flour  emery. 

Stourbridge  loam  is  by  no  means  the  only  ingredient  used  in  uniting  the 
particles  of  emery,  as  many  other  substances  answer  as  well ;  such  as  slate, 
Yorkshire  gritstone,  crocus,  &c.,  and  in  this  way  the  hardness  and  cut  of  the 
emery  stone  may  be  varied  to  a  great  extent. 

Most  of  the  grinders  made  of  the  Emery  stone  are  formed  with  central 
holes,  so  as  to  admit  of  being  attached  to  the  lathe  upon  appropriate  chucks 
or  spindles  ;  and  the  substance  is  so  porous  as  to  absorb  much  water,  which 
is  gradually  thrown  to  the  surface  by  the  centrifugal  motion  so  as  to  keep 
the  edge  conveniently  moist,  or  with  excessive  velocity,  the  water  is  thrown 
off  as  in  trundling  a  mop.  Mr.  Barclay  has  made  the  disks  of  various  dia- 
meters from  £  inch  to  8  or  10  inches  diameter,  but  the  difficulty  increases 
with  the  size,  as  the  large  ones  are  liable  to  warp  and  crack  in  the  firing. 

When  the  emery  stone  laps  are  required  to  have  plane  surfaces,  angular 
or  convex  edges,  &c.,  that  could  not  be  readily  moulded,  the  composition  is 
partially  fired  at  a  low  heat,  then  turned  in  a  lathe  to  the  specific  form,  and 
the  firing  at  a  nearly  white-heat  completes  the  manufacture. 

The  coarse  emery  stone  has  been  tried  in  cutting  glass,  and  is  reported 
then  to  fulfil  in  itself  the  offices,  first,  of  the  iron  disk  fed  with  sand  used  in 
roughing,  and  secondly,  of  the  Lancashire  fine  grit  stone  used  in  smoothing ; 
as  when  of  proper  consistence,  the  artificial  emery  stone  cuts  as  quickly  as 
the  former,  and  as  smoothly  as  the  latter,  and  has  the  advantage  of  main- 
taining its  form  in  an  eminent  degree. 

Small  fragments  of  these  disks,  spoiled  in  the  firing,  have  been  successfully 
used  in  scrubbing  off  the  rough  sand  coat  of  door  plates,  mouldings,  &c., 
cast  in  brass,  &c.,  and  indeed  the  Patent  Emery  Stone  eminently  deserves 
more  extended  use  than  it  has,  up  to  the  present  time,  attained, 

It  remains  to  be  observed  that  Mr.  Barclay  took  up  the  subject  of  the 
Artificial  Emery  Stone  from  necessity,  as  in  his  professional  employment  of 
making  artificial  teeth  and  gums,  of  a  kind  of  hard  porcelain,  he  found  the 
small  grindstones,  (tediously  prepared  by  rubbing  down  waste  flakes  of  the 
Yorkshire  stone  used  for  paving  into  flat  plates,  and  which  are  afterwards 
drilled  and  turned  to  the  requisite  forms,)  wore  out  amazingly  quick,  even 
when  assisted  by  coarse  sand  and  water  ;  but  the  present  scheme  fulfils  the 
office  of  the  grindstone  in  an  admirable  manner  ;  and  some  small  artificial 
stones  made  as  above  have  been  in  almost  daily  use  for  3  or  4  years. 

VOL.  III.  D 


1059         DESCRIPTIVE    CATALOGUE    OF    APPARATUS,    MATERIALS, 


. 


The  project  bears  an  evident  analogy  to  Mr.  Prosser's  Patent 
making  buttons,  various  articles,  and  even  fire  bricks,  out  of  dry  clay  in 
powder  compressed  in  a  mould  and  afterwards  burned,  and  it  offers  certain 
advantages  over  the  corundum  wheels  used  in  India,  and  described  under 
the  head  CORUNDUM. 

EMERALDS. — These  valuable  stones,  the  finest  of  which  are  found  in  Peru,  are 
considered  to  be  very  soft  gems,  and  in  consequence  they  require  more  than 
ordinary  care  in  their  polishing,  and  still  do  not  admit  of  such  acute  angles 
and  edges  being  given  to  them  as  to  many  of  the  harder  gems.  The 
Emerald  is  worked  just  like  CARNELIAN. 

ENAMELS. — These  are  metallic  surfaces  covered  with  a  thin  coating  of  glass  of 
various  colours,  and  which  is  sometimes  partially  transparent,  but  generally 
opaque.  The  enamel  or  glass  is  ground  to  powder,  mixed  with  some  vehicle, 
such  as  turpentine,  or  oil  of  spike,  and  spread  on  as  a  thick  coating  of 
paint,  and  when  dried,  the  whole  is  heated  just  sufficiently  to  fuse  the  enamel, 
and  cause  it  to  adhere  to  the  metal. 

The  work  is  placed  within  a  muffle,  which  is  in  many  cases  a  miniature 
arched  vault  open  at  one  end,  placed  in  the  midst  of  a  small  furnace,  and 
surrounded  by  burning  fuel,  which  keeps  it  at  the  red  heat,  although  the 
fuel  cannot  possibly  touch  the  work.  In  other  cases  the  furnace  is  made  of 
sheet  iron  ;  it  then  measures  externally  about  20  inches  long,  12  wide,  and 
10  deep,  and  is  mounted  on  wrought  iron  legs  that  support  it,  so  that  the 
opening  or  door,  which  is  at  the  one  end,  may  be  on  the  level  with  the  eye  of 
the  artist,  whilst  from  the  opposite  end  proceeds  the  flue  leading  into  a 
chimney.  The  whole  apparatus  bears  some  resemblance  to  a  German 
stove,  or  rather,  to  a  laundry  stove  considerably  elevated,  but  the  muffle,  or 
a  heated  chamber  corresponding  therewith,  is  always  provided  for  the 
reception  of  the  work  to  be  enamelled  to  protect  the  same  from  the  flame 
and  smoke  of  the  fuel. 

Many  of  the  enamelled  works  can  hardly  be  said  to  be  polished  artificially, 
as  the  lustre  is  produced  simply  by  the  process  of  fusion  ;  thus  the  enamelled 
faces  of  watches,  when  the  ground  has  been  fired,  only  require  the  figures  to 
be  added,  as  the  vitreous  surface  is  mostly  smooth  enough  from  the  fusion 
without  being  polished  ;  and  in  less  favourable  cases  the  work  is  only  ground 
to  a  level  but  dull  surface,  and  afterwards  just  raised  to  the  melting  point,  so 
as  to  fuse  the  surface,  and  thereby  give  it  the  polish. 

The  backs  of  gold  watches  and  numerous  articles  of  jewellery,  including 
mourning  rings,  are  so  enamelled  as  to  show  various  devices  or  inscriptions 
in  gold,  upon  a  ground  or  general  surface  of  enamel ;  in  this  case  the  work  is 
engraved,  all  the  parts  where  the  enamel  is  to  appear  being  cut  away  by  the 
graver,  and  the  spaces  are  afterwards  filled  in  with  the  pulverised  enamel, 
which  is  burnt  in,  and  lastly,  the  whole  is  polished  down  to  a  uniform  surface. 

Formerly  nearly  all  the  enamelled  works  were  polished  by  the  lapidaries, 
who  used,  1st,  the  horizontal  lead  mill  with  fine  emery  for  grinding  ;  2ndly, 


AND    PROCESSES    FOR    GRINDING    AND    POLISHING.  1060 

lead  with  rottcnstone  and  water ;  and  3rdly,  the  leather  lap  or  buff  wheel 
with  putty  powder.  But  the  enamellers  of  the  present  day  mostly  polish 
their  own  work,  and  employ  either  an  ordinary  lathe  with  a  mandrel  upon 
which  the  laps  are  screwed  like  chucks,  the  cylindrical  edges  of  the  laps 
being  alone  used,  or  else  they  employ  a  polishing  lathe  similar  to  those  of 
cutlers  and  others. 

The  French  enamellers  commonly  select  instead  of  emery,  a  hard  white 
pulverised  porcelain,  called  white  emery,  which  is  manufactured  at  the  Royal 
Manufactory  of  Porcelain  at  Sevres,  and  they  afterwards  polish  with  yellow 
tripoli ;  the  first  is  applied  on  a  lead  or  wooden  wheel,  and  the  latter  on  a  buff. 

When  enamels  are  polished  by  hand,  the  work  is  first  roughed  down  with 
slips  of  water  of  ayr  stone  and  water,  used  after  the  manner  of  a  file  ;  after 
which  the  different  artists  use  slips  of  boxwood,  mahogany,  or  metal,  first, 
with  pumice-stone,  and  then  with  crocus,  nearly  as  for  gold. 

FACETS,  a  few  words  are  given  on  the  cutting  of  the  facets  or  gems  at  the  con- 
elusion  of  the  article  on  Carnelian,  but  the  subject  will  be  considered  more 
at  length  in  the  chapter  on  lapidary  work. 

FAYRER'S  SWING  HONE.— This  is  a  flat  and  parallel  slip  of  brass,  in  form 
like  a  hone,  but  with  pivots  at  the  ends  by  which  it  is  suspended  in  two 
notches,  so  that  this  metal  lap,  or  factitious  hone,  may  accommodate  itself  to 
the  angle  at  which  the  razor  or  other  instrument  is  applied  to  it.  The  one 
side  of  the  bi'ass  is  first  used  with  fine  oilstone  powder  and  oil,  afterwards 
the  second  side  with  pulverised  water  of  ayr  stone  and  oil,  and  the  razor 
strop  is  afterwards  resorted  to,  see  Trans.  Soc.  of  Arts,  vol.  48,  p.  248. 

FELSPAR. — The  fine  varieties  of  this  siliceous  mineral,  display  most  beautiful  and 
varied  iridescent  colours  ;  namely,  blues  and  greens  in  the  Labrador  Felspar, 
a  beautiful  apple  green  in  the  Amazon  Stone,  and  a  pearly  white  in  the 
Adularia  or  Moonstone,  the  colours  are  best  seen  when  the  specimens  are 
polished,  which  is  effected  as  with  Carnelian  although  Felspar  is  scarcely  so 
hard. 

FELT  or  Felted  Cloth  is  very  much  used  for  polishing  especially  for  marble.  See 
CLOTH  and  MARBLE. 

> 
FISH  SKIN  is  the  skin  of  the  Dog  Fish,  and  some  others  which  is  dried  as  its 

only  preparation.  The  scales  of  the  skin  are  hard  and  pointed  and  stand  up 
obliquely,  so  that  they  cut  or  abrade  very  effectually  in  the  one  direction, 
but  not  in  the  other.  Fish  skin  is  more  durable  but  less  generally  con- 
venient than  glass  paper,  to  which  it  probably  gave  rise.  It  is  however  now 
but  little  used  in  polishing,  although  in  clearing  off  rounded  and  irregular 
works,  as  in  pattern  making,  from  the  fish  skin  being  somewhat  rigid,  when 
bent  round  the  finger  it  may  be  almost  used  as  a  file,  and  it  has  the  further 
advantage  of  leaving  nothing  behind  it,  whereas,  glass  paper  commonly  deposits 
D  2 


1061        DESCRIPTIVE    CATALOGUE    OF    APPARATUS,    MATERIALS, 

some  of  the  particles  of  glass  in  the  surface  of  the  wood,  to  the  detriment 
of  any  tools  subsequently  employed.  The  fins  should  be  selected  for  fine 
works. 

FLANDERS  BRICKS,  these  which  are  now  equally  or  better  known  as  Bath 
bricks,  are  made  in  large  quantities  of  a  clay  found  at  Bridgewater,  and  which 
contains  a  considerable  proportion  of  fine  sand.  Besides  the  extensive 
employment  of  these  bricks  for  domestic  purposes,  and  in  making  founders 
cores,  they  are  sometimes  employed  when  rubbed  to  powder,  in  polishing 
bone,  ivory,  and  soft  metals,  and  also  in  dressing  cutlers  dry  buff  wheels, 
boards  for  cleaning  table  knives,  &c.  Trent  sand  is  preferable  when  it  can 
be  procured. 

FLAT  SURFACES. — The  principal  modes  of  grinding  flat  or  plane  surfaces,  will 
be  described  in  Chap.  XXXIII.  sect.  1. 

FLINT  is  not  frequently  polished  by  the  lapidary  but  is  then  treated  like  Carnelian. 
Until  of  late  years  one  of  the  greatest  uses  of  this  substance  was  for  procur- 
ing fire,  but  percussion  caps  and  Congreve  matches  have  nearly  superseded 
this  employment  of  flint,  which  still  however  enters  largely  into  the  composi- 
tion of  porcelain,  and  has  given  the  name  to  Flint  Glass,  although  hi  this 
manufacture  it  is  now  rejected  in  favor  of  the  more  available  article,  the 
pure  sand  obtained  from  Alum  Bay,  Isle  of  Wight,  Maidstone,  and  elsewhere. 
Flint  is  employed  in  the  mechanical  arts,  as  the  "  louldering  stone"  for  rubbing 
down  to  a  smooth  face  the  laps,  buffs  and  glaze  wheels  of  the  cutler,  and 
pulverized  flint  has  also  obtained  the  employment  described  in  the  succeeding 
article. 

Flint.  The  late  Mr.  Larkin  in  finishing  his  beautiful  wood  models  of 
crystals,  employed  calcined  flint  pulverized  and  glued  upon  wooden  face 
wheels,  as  more  fully  described  under  the  heads  GLASS  PAPER,  and  WHEELS, 
article  59. 

FLUOR  SPAR. — This  substance  from  the  confusion  in  the  arrangement,  and 
the  frangibility  of  its  crystals  requires  a  peculiar  and  careful  treatment 
whilst  being  turned  into  form,  and  which  is  described  at  page  168-9  of  the 
first  volume.  The  smoothing  and  polishing  are  conducted  almost  the  same 
as  in  marble,  but  as  fluor  spar  requires  a  longer  continuance  of  the  polishing 
process,  it  demands  considerable  care  to  preserve  the  square  fillets  of  the 
work  from  being  rounded  in  the  polishing,  and  with  which  object  the  powders 
are  sometimes  applied  on  small  square  slips  of  metal  or  wood,  the  sides  of 
which  are  used  somewhat  as  a  file  so  as  to  present  a  superior  degree  of 
definition  and  permanence  in  the  form  of  the  polishers,  than  would  be  obtained 
by  the  exclusive  use  of  cloth  applied  with  the  fingers. 

The  lapidary  pursues  the  same  method  in  polishing  fluor  spar  as  carnelian, 
but  he  does  not  succeed  so  well  as  the  Derbyshire  workmen,  and  only  pro- 
duces what  may  be  termed  "a  greasy  polish." 


AND    PROCESSES    FOR    GRINDING    AND    POLISHING.  1062 

F  REESTONES.-  Few  or  none  of  these  admit  of  being  polished,  but  many  of  them  are 
rubbed  smooth  ;  the  rubber  being  in  general  a  smaller  piece  of  the  same  kind 
of  stone,  sometimes  used  alone,  at  other  times  with  a  plentiful  supply  of  sharp 
sand  and  water.  In  turned  works,  the  stone  rubber  is  smaller  and  held  in 
the  hand,  the  process  being  frequently  conducted  dry,  and  without  additional 
sand. 

GANNISTER  STONE  a  species  of  slaty-stone  somewhat  resembling  the  Charnley 
Forest,  or  Mount  Sorrel  stone,  and  which  is  abundantly  used  in  repairing 
the  macadamized  roads  around  Sheffield.  When  calcined,  pulverized,  sifted, 
and  applied  on  a  straight  buff  stick  of  the  bull  neck  leather,  the  Gannister 
stone  is  preferred  to  most  other  materials,  for  smoothing  the  threaded  shoul- 
ders of  pocket  knives  after  they  have  been  filed,  as  it  is  considered  better  to 
preserve  the  keen  threads  or  projecting  ridges  of  the  shoulders  than  other 
abrasive  powders.  The  work  is  completed  on  a  wheel  brush  fed  with  fine 
emery  and  oil,  followed  by  another  with  crocus  and  oil. 

GARNETS  are  worked  by  the  lapidary  just  like  Carnelian,  so  far  as  the  succes- 
sion of  the  tools  is  concerned,  the  production  of  the  facets  is  further  noticed 
in  the  chapter  on  lapidary  work.  The  fine  large  Garnets  when  cut  en 
cabochon,  or  with  a  rounded  face,  are  known  as  Carbuncles  and  are  sup- 
posed to  be  the  gems  so  designated  also  in  the  Scriptures. 

GERMAN  HONE.— See  HONE  SPATES,  also  the  article  on  setting  razors  in  Chap. 
XXXII. 

GLASS  is  polished  in  various  different  manners,  some  of  which  are  else- 
where particularized.  Thus  Plate  Glass,  is  roughed  with  sand,  smoothed 
with  emery,  and  polished  with  crocus.  See  Chap.  XXXIII.  Sect.  1.  Glass 
Lenses,  are  roughed  out  with  sand,  figured  with  emery,  and  polished  with 
putty  powder.  See  Chap.  XXXIII.  Sect.  4.  Cut  glass  for  household  purposes 
and  toys,  is  roughed  with  sand,  smoothed  on  a  Lancashire  grit-stone,  then 
with  pumice-stone,  and  lastly  is  polished  with  putty  or  rottenstone  see  Chap. 
XXXIII.  Sect.  5. 

Lapidaries  in  cutting  glass  for  jewellery  adopt  the  mode  described  in  this 
catalogue  as  used  by  them  for  alabaster,  with  the  exception  that  they  omit 
the  wooden  mill. 

Glass  is  used  as  a  vehicle  for  polishing  powders  by  watchmakers,  watch- 
jewellers,  and  some  others.  See  BRASS,  article  6,  and  MACHINERY,  article  13. 

GLASS  PAPER. — In  making  this  useful  article,  the  fragments  of  broken  wine 
bottles  are  carefully  washed  to  remove  all  dirt,  the  glass  is  then  crushed 
under  a  runner,  and  sifted  into  about  six  sizes  as  in  manufacturing  emery. 
The  paper  is  brushed  over  with  thin  glue,  and  the  pulverized  glass  is  then 
dusted  over  it  from  a  sieve,  which  completes  the  process.  Sometimes  two 
coats  of  glue  and  glass  are  applied,  or  Venetian  red  is  mixed  with  the  glue  to 


1063       DESCRIPTIVE    CATALOGUE    OF    APPARATUS,    MATERIALS, 

give  that  tint  to  the  glass  and  sand  papers,  and  under  Edward's  Patent,  thin 
cotton  cloth  is  used  instead  of  paper,  as  the  vehicle  for  the  glass. 

See  FLINT,  an  article  recommended  instead  of  glass  for  the  above  and 
other  purposes. 

GLAZERS,  or  GLAZING  WHEELS. — Wooden  wheels  covered  with  leather  when 
charged  with  fine  emery  receive  the  above  names,  but  when  supplied  with 
crocus  and  used  for  finer  purposes  they  are  called  polishers.  Such  wheels 
charged  with  emery  cake,  bouldered  and  waxed  to  deaden  the  emery  are 
much  used  at  Sheffield.  See  WHEELS,  articles  50  and  51. 

GOLD  is  in  general  polished  much  the  same  as  silver  although  some  variation  is 
made  as  works  in  gold  are  in  general  much  smaller  and  do  not  require  such 
active  means  as  those  in  silver. 

1. — Gold  is  1st  polished  with  water  of  ayr  stone  in  the  stick  used  with  water,  2ndly 
with  slips  of  wood  with  coarse  crocus,  and  3dly  with  a  buff  stick  and  fine 
crocus  or  rouge.  The  black  polish  which  is  so  much  esteemed,  is  given  with 
the  naked  hand  and  rouge,  but  the  perfection  of  the  polish  depends  on  the 
peculiar  texture  of  the  skin,  as  the  hands  of  some  individuals  do  not  at  all 
answer  the  purpose. 

2. — FLAT  WORKS  IN  GOLD  are  treated  by  cutlers  and  others  1st  with  water  of 
ayr  stone  in  the  stick  with  water,  2ndly  charcoal  in  the  stick  with  water, 
3dly  boxwood  and  rouge  very  nearly  dry. 

3. — CUT  on  FACETTED  GOLD  is  wrought  upon  pewter  laps  with  crocus,  the  process 
closely  resembles  the  cutting  of  facets  on  gems,  see  Chap.  XXXIV.,  but  the 
work  is  guided  by  the  fingers  alone. 

GRANITE,  after  having  been  worked  into  form  with  heavy  dumpy  picks,  and 
then  with  the  hammer  and  chisel  or  diamond  point,  is  1st  ground  to  a 
moderately  smooth  surface  with  a  heavy  iron  plate  fed  with  sharp  sand  or 
coarse  emery  and  water,  and  put  into  reciprocal  motion,  or  in  turned  works 
the  granite  is  put  in  quick  circular  revolution  against  the  rubber.  2ndly  the 
work  is  smoothed  with  another  iron  plate  and  coarse  flour  emery.  3dly  it  is 
further  advanced  by  wooden  rubbers  with  fine  flour  emery,  the  rubbers 
being  made  the  end- way  of  the  wood.  4thly  and  lastly  crocus  is  used  on 
thick  felt  laid  on  wood  or  metal.  On  account  of  the  softness  of  the  mica 
compared  with  the  quartz  and  felspar,  which  together  constitute  the  granite, 
the  hard  rubbers  must  be  persevered  in  until  near  the  conclusion,  to  keep 
the  work  flat,  otherwise  the  mica  is  too  quickly  worn  away,  and  leaves 
minute  hollows.  Sometimes  lumps  of  granite  are  used  as  rubbers  instead  of 
the  iron  plates. 

2. — GRANITE,  when  worked  by  the  lapidary  is  slit  and  roughly  ground  in  the  com- 
mon mode  adopted  both  with  CARNELIAN  and  ALABASTER,  namely  the  slicer 
with  diamond  powder  and  the  roughing  or  lead  mill  with  coarse  emery  ; 
afterwards  it  is  found  best  to  smooth  it  on  a  mahogany  wheel  with  flour 


AND    PROCESSES    FOR    GRINDING    AND    POLISHING.  1064 

emery,  and  to  polish  it  on  the  lead  wheel  with  rottenstone  ;  but  it  requires 
great  care  to  prevent  the  soft  mica  from  being  unduly  worn  away. 

GREENSTONE. — See  HONE  SLATES,  also  the  article  on  setting  razors,  Chap.  XXXII. 

GRINDSTONE. — Grit  Stones  or  Grinding  Stones  are  varieties  of  sandstones,  some 

of  which  are  described. 

1. — t(  NEWCASTLE  GRINDSTONES  abound  in  the  coal  districts  of  Northumberland, 
Durham,  Yorkshire  and  Derbyshire ;  and  are  selected  of  different  degrees  of 
density  and  coarseness,  best  suited  to  the  various  manufactures  of  Sheffield 
and  Birmingham,  for  grinding  and  giving  a  smooth  and  polished  surface  to 
their  different  wares." 

2.—"  BILSTON  GRINDSTONE  is  a  similar  description  of  stone,  of  great  excellence,  it 
is  of  a  lighter  colour,  much  finer  and  of  a  very  sharp  nature,  and  at  the  same 
time  not  too  hard.  It  is  confined  to  a  very  small  spot  of  limited  extent  and 
thickness,  in  the  immediate  vicinity  of  Bilston,  in  Staffordshire,  where  it 
lies  above  the  coal,  and  is  now  quarried  entirely  for  the  purpose  of  grind- 
stones." 

3. — "  CARPENTERS'  RUBSTONE  is  a  hard  close  variety,  used  as  a  portable  stone  for 
sharpening  tools  by  rubbing  them  on  the  flat  stone  instead  of  grinding.  It 
is  also  much  employed  for  the  purpose  of  giving  a  smooth  and  uniform 
surface  to  copper  plates  for  the  engraver." 

A  much  softer  variety  of  sandstone,  is  usually  cut  into  a  square  form  from 
eight  to  twelve  inches  long,  in  which  state  they  are  used  dry  by  shoe-makers, 
pocket-book  makers,  cork-cutters,  and  others,  for  giving  a  sort  of  rough  edge 
to  their  bladed  knives  and  instruments  of  a  similar  description. 

4. — "  DEVONSHIRE  BATTS. — A  porous  fine-grained  sandstone  hi  considerable  repute, 
from  the  quarries  of  Black  Down  Cliffs,  near  Collumpton." 

5. — "  YORKSHIRE  GRIT  is  a  variety  not  at  all  applied  as  a  whetstone,  but  is  in  con- 
siderable use  as  a  polisher  of  marble,  and  of  copper  plates  for  engravers." 

6. — "  CONGLETON  GRIT  is  a  very  similar  stone  of  a  softer  nature,  and  made  use 
of  by  the  same  description  of  workmen." 

7. — SHEFFIELD  GRINDSTONE  is  a  hard  coarse  grit  stone  used  for  grinding  large  files, 
and  similar  purposes,  it  is  obtained  from  Hardsley  which  lies  about  1 4  miles 
north  of  Sheffield. 

8. — WICKERSLEY  GRINDSTONES  are  very  generally  used  in  Sheffield  for  most  pur- 
poses of  grinding,  as  knives,  scissors,  razors,  saws,  and  edge  tools  generally. 
Wickersley  stones  are  quarried  at  a  village  of  that  name  about  9  miles  east 
of  the  town  of  Sheffield. 

9. — SHEFFIELD  BLUESTONEis  a  finer  grained  stone  than  either  of  the  last  two  kinds, 
and  is  very  generally  used  at  Sheffield  for  finishing  the  grinding  of  articles 
of  cutlery,  that  have  been  prepared  on  the  Wickersley  stones.  The  act  of 
grinding  on  a  blue  stone  is  called  "wkittening"  and  the  blades  of  table  and 
pocket  knives  are  always-thus  treated  in  Sheffield.  The  bluestones  are  found 
very  abundantly  in  the  neighbourhood  of  Sheffield  at  from  i  to  H  miles  on 
the  north  and  south  sides  of  the  town. 


1065         DESCRIPTIVE    CATALOGUE    OF    APPARATUS,    MATERIALS, 

GUM  LAC. — See  LAC  ;  also  CORUNDUM. 

GUN  METAL  is  polished  like  brass,  which  see. 

GYPSUM.— See  ALABASTER. 

HACKING,  a  process  employed  in  dressing  rough  grindstones,  by  notching  or 
checkering  the  high  parts  with  a  hack  hammer,  which  resembles  a  small 
adze  of  from  one  to  three  pounds  weight,  fitted  with  a  short  handle.  The 
process  is  fully  described  under  WHEELS,  article  15. 

2. — The  periphery  or  face  of  soft  metal  laps  and  wooden  glaze  wheels,  are  also 
in  some  cases  hacked  by  the  cutlers,  with  a  very  light  sharp  hammer, 
the  edge  of  which  should  be  as  keen  as  a  chisel,  and  used  very  delicately  ; 
but  by  far  the  more  usual  course  is  to  score  the  edges  of  the  wheels  while 
they  are  at  rest,  with  a  pointed  knife,  which  injures  these  tools  less  and 
entirely  avoids  the  risk  of  spoiling  the  edge  or  angle  of  the  lap,  which 
should  be  scrupulously  preserved. 

3. — Lapidaries  employ  an  entirely  different  mode  of  hacking  or  jarring  their 
leaden  pewter  and  copper  polishing  wheels,  which  are  used  with  rottenstone 
and  water,  as  fully  described  under  the  head  CARNELIAN. 

HARDWOOD.— See  WOOD. 

HELIOTROPE. — See  BLOODSTONE,  and  also  the  article  on  CARNELIAN. 

HONE  SLATES. — A  mineralogical  distinction  for  various  slaty  stones  that  are 
used  in  straight  pieces  or  slabs  for  whetting  or  sharpening  the  edges  of  tools 
subsequently  to  their  having  been  ground  on  revolving  grindstones.  The 
following  quotations  are  from  Mr.  Knight's  paper  in  the  Trans,  of  the  Society 
of  Arts,  vol  50,  page  233. 

1. — "  NORWAY  RAGSTONE. — This  is  the  coarsest  variety  of  the  hone  slates.  It  is 
imported  in  very  considerable  quantities  from  Norway  in  the  form  of  square 
prisms,  from  nine  to  twelve  inches  long,  and  one  to  two  inches  diameter, 
gives  a  finer  edge  than  the  sandstones,  and  is  in  very  general  use." 

2. — "  CHARNLEY  FOREST  STONE  is  one  of  the  best  'substitutes  for  the  Turkey  oil- 
stone, and  much  in  request  by  joiners  and  others,  for  giving  a  fine  edge 
to  various  tools  and  also  penknives.  It  has  hitherto  been  found  only  on 
Charnwood  Forest,  near  Mount  Sorrel,  in  Leicestershire."  The  best  Charu- 
ley  Forest  Stone,  is  by  some  considered  to  come  only  from  the  Whittle  Hill 
Quarry,  the  other  stones  from  the  neighbourhood  are  more  pinny,  or  present 
hard  places. 

3. — <(  AYR- STONE,  SCOTCH-STONE,  OR  SNAKE-STONE,  is  most  in  request  as  a  polish- 
ing stone  for  marble  and  copper-plates ;  but  the  harder  varieties  have  of  late 
been  employed  as  whetstones."  These  stones  should  always  be  kept  damp 
or  even  wet,  to  prevent  their  becoming  hard. 

4. — "  IDWALL  OR  WELSH  OIL-STONE   is  generally  harder,  but  in  other  respects 


AND    PROCESSES    FOR    GRINDING   AND    POLISHING.  1066 

differs  but  little  as  a  whetstone  from  the  Charnley  Forest.  It  is  obtained 
from  the  vicinity  of  Llyn  Idwall,  in  the  Snowdon  district  of  North  Wales," 
and  is  now  in  more  general  use  for  small  articles  of  cutlery  than  the  Charnley 
Forest  Stone. 

5 "DEVONSHIRE  OIL-STONE  is  an  excellent  variety  for  sharpening  all  kinds  of 

thin  edged  broad  instruments,  as  plane-irons,  chisels,  &c.,and  deserves  to  be 
better  known.  This  stone  was  first  brought  into  notice  by  Mr  John  Taylor, 
who  met  with  it  in  the  neighbourhood  of  Tavistock,  and  sent  a  small  parcel 
to  London  for  distribution  ;  but  for  want  of  a  constant  and  regular  supply, 
it  is  entirely  out  of  use  here." 

6. — "  CUTLERS'  GREEN  HONE  is  of  so  hard  and  close  a  nature,  that  it  is  only 
applicable  to  the  purposes  of  cutlers  and  instrument  makers,  for  giving  the 
last  edge  to  the  lancet  and  other  delicate  surgical  instruments.  It  has 
Tiitherto  been  only  found  in  the  Snowdon  mountains  of  North  Wales." 

7. — "  GERMAN  RAZOR  HONE. — This  is  universally  known  throughout  Europe, 
and  generally  esteemed  as  the  best  whetstone  for  all  kinds  of  the  finer 
descriptions  of  cutlery.  It  is  obtained  from  the  slate  mountains  in  the  neigh- 
bourhood of  Ratisbon,  where  it  occurs  in  the  form  of  a  yellow  vein  running 
virtually  into  the  blue  slate,  sometimes  not  more  than  an  inch  in  thickness, 
and  varying  to  twelve  and  sometimes  eighteen  inches,  from  whence  it  is 
quarried,  and  then  sawed  into  thin  slabs,  which  are  usually  cemented  into  a 
similar  slab  of  the  slate  to  serve  as  a  support,  and  in  that  state  sold  for  use. 
That  which  is  obtained  from  the  lowest  part  of  the  vein  is  esteemed  the  best 
and  termed  old  rock."  The  German  Hone  is  now  used  almost  exclusively 
for  razors,  as  being  very  soft,  it  is  cut  by  any  instrument  applied  at  an  angle, 
and  not  laid  flat  down  as  a  razor  invariably  is. 

8. — «  BLUE  POLISHING  STONE  is  a  dark  slate  of  very  uniform  character ;  in  appear- 
ance not  at  all  laminated  ;  is  in  considerable  use  among  jewellers,  clock- 
makers,  and  other  workers  in  silver  and  metal,  for  polishing  off  their  work, 
and  for  whose  greater  convenience  it  is  cut  into  lengths  of  about  six  inches, 
and  from  a  quarter  of  an  inch  to  an  inch  or  more  wide,  and  packed  up  in 
small  bundles  of  from  six  to  sixteen  in  each,  and  secured  by  means  of  withes 
of  osier,  and  in  that  state  imported  for  use." 

0. — "  GREY  POLISHING  STONE  is  a  stone  of  very  similar  properties  to  the  blue,  but 
of  a  somewhat  coarser  texture  and  paler  colours.  Its  uses  are  the  same  and 
both  kinds  are  manufactured  near  Ratisbon." 

10. — "  WELSH  CLEARING-STONE  is  a  soft  variety  of  hone-slate,  the  use  of  which  is 
confined  to  curriers,  and  by  them  employed  to  give  a  fine  smooth  edge  to  their 
broad  and  straight-edged  knives  for  dressing  leather.  They  are  always  cut 
of  a  circular  form." 

11. — PERUVIAN  HONE  has  been  recently  introduced  as  a  whetstone,  and  is  said  to 
be  imported  from  South  America.  It  cuts  freely  with  either  oil  or  water, 
and  is  suitable  for  sharpening  large  tools  that  do  not  require  a  very  fine  edge. 

12. — WELSH  HONE.    See  article  4. 

13.— OILSTONE  WHITE  AND  BLACK.  These  are  varieties  of  the  Turkey-stone. 
See  OILSTONE. 


1067         DESCRIPTIVE    CATALOGUE    OF    APPARATUS,    MATERIALS, 

14. — ARKANSAS  STONE,  from  N.  AMERICA  is  of  unequal  texture  and  cuts  slowly. 

15. — BOHEMIAN  STONES  are  imported  from  Germany,  and  are  used  by  jewellers 
in  the  same  manner  as  the  blue  and  grey  polishing  stones  for  polishing  small 
works,  such  as  the  settings  around  gems.  The  Bohemian  stones  cut  well,  and 
keep  a  good  point  for  small  work. 

HORN  handles  for  razors,  knives,  and  similar  works  when  moulded  (see  vol.  1, 
page  125)  are  scraped  and  then  buffed  with  Trent  sand  and  oil,  and  after- 
wards with  rottenstone  and  oil  as  more  fully  explained  under  the  head 
"  Tortoiseshell ;"  but  upon  which  latter  material  the  Trent  sand  is  not 
used  in  its  natural  state,  as  it  would  be  too  coarse  and  vigorous  in  its  action 
on  that  soft  and  expensive  substance  ;  for  buffing  tortoiseshell  therefore  the 
Trent  sand  is  first  calcined  and  pounded,  and  then  passed  through  a  muslin 
sieve.  See  article  TORTOISESHELL. 

Horn  is  sometimes  used  by  watchmakers  as  a  vehicle  for  the  application  of 
polishing  powders  to  flat  works.     See  MACHINERY,  article  1 3. 

HYACINTH.— See  ZIRCON. 

IDWALL  STONE.— See  HONE  SLATES,  article  4. 

IRON. — The  modes  of  polishing  the  parts  of  machinery  made  in  wrought  and  cast 
iron,  are  described  in  the  general  article  MACHINERY  in  this  Catalogue.  See 
also  WROUGHT-IRON  and  CAST-IRON. 

IRON  STONE. — A  straight  slab  of  the  haematite  iron  ore,  ground  flat  on  the  one 
face,  is  sometimes  used  by  the  Sheffield  cutlers  after  the  yellow  German 
hone,  in  polishing  the  "  cannell  "  or  chamfers  made  by  the  German  hone  in 
setting  razors. — The  iron  stone  is  very  hard,  and  leaves  a  very  smooth  edge, 
almost  fulfilling  the  purpose  of  the  razor  strop,  but  it  must  be  used  very 
lightly  and  sparingly.  See  the  article  on  setting  razors,  Chap.  XXXIII.  Sect.  2. 

IVORY. — The  modes  of  polishing  objects  made  of  this  useful  and  ornamental  sub- 
stance, differ  according  to  the  nature  of  the  works  ;  and  although  the 
remarks  here  offered  refer  especially  to  the  ivory  of  the  elephant,  that  of  the 
tusks  of  other  animals,  also  the  corosos  or  vegetable  ivory,  and  bone  are 
treated  nearly  or  quite  the  same,  when  applied  to  similar  uses. 

TURNED  WORKS. 

1. — TURNED  WORKS  with  plain  surfaces  may  in  general  be  left  so  smooth  from  the 
tool  as  to  require  but  very  little  polishing,  a  point  always  aimed  at  with 
superior  workmen  by  the  employment  of  sharp  tools.  In  the  polishing  of 
turned  works  very  fine  glass  paper  or  emery  paper  is  1st  used,  and  it  is 
rendered  still  finer  and  smoother  by  rubbing  two  pieces  together  face  to  face  ; 
2iidly,  whiting  and  water  as  thick  as  cream  is  then  applied  on  wash  leather, 


AND    PROCESSES    FOR   GRINDING    AND    POLISHING.  1068 


linen,  or  cotton  rag,  which  should  be  thin  that  the  fingers  may  the  more 
readily  feel  and  avoid  the  keen  fillets  and  edges  of  the  ivory  work,  that  would 
be  rounded  by  excessive  polishing  ;  3rdly,  when  the  work  feels  smooth,  or  to 
hang  less  to  the  rag  than  at  first,  the  work  is  washed  with  clean  water  on  the 
same  or  another  rag  ;  4thly,  it  is  rubbed  with  a  clean  dry  cloth  until  all  the 
moisture  is  absorbed,  and  lastly  a  very  minute  quantity  of  oil  or  tallow  is 
put  on  the  rag  to  give  a  gloss. 

Scarcely  any  of  the  oil  remains  behind,  and  the  apprehension  of  its  being 
absorbed  by  the  ivory  and  disposing  it  to  turn  yellow,  may  be  discarded  ; 
indeed  the  quantity  of  oil  used  is  quite  insignificant,  and  its  main  purpose  is 
to  keep  the  surface  of  the  ivory  slightly  lubricated,  so  that  the  rag  may  not 
hang  to  it  and  wear  it  into  rings  or  groovy  marks.  Putty  powder  is  some- 
times used  for  polishing  ivory  work,  but  it  is  more  expensive  and  scarcely 
better  suited  than  whiting  which  is  sufficiently  hard  for  the  purpose. 

2. — TURNED  WORKS  .consisting  of  many  parts  are  best  polished  separately,  as  they 
are  then  more  accessible,  and  the  whiting  and  water  do  not  penetrate  and  clog 
the  joinings  of  the  several  parts,  and  prevent  their  easy  separation.  Accurate 
workmen  frequently  polish  screw  threads,  in  order  to  make  them  move  the 
more  easily,  and  to  endure  the  longer  without  wearing  loose  ;  this  is  some- 
times done  with  screws  in  ivory  and  the  woods,  as  well  as  those  in  the  metals, 
and  is  to  be  highly  recommended. 

3. — TURNED  WORKS  ornamented  with  the  eccentric  chuck,  revolving  cutters,  &c. 
also  require  to  be  cut  with  exceedingly  sharp  tools,  in  order  that  but  little 
polishing  may  be  necessary. 

The  polishing  of  irregular  surfaces  is  generally  done  with  a  moderately 
hard  nail  brush,  supplied  with  whiting  and  water,  and  lightly  applied  in 
all  directions,  to  penetrate  every  interstice  ;  after  a  period  the  work  is 
brushed  with  plain  water  and  a  clean  brush,  to  remove  every  vestige  of  the 
whiting.  The  ivory  is  dried  by  wiping  and  pressing  it  with  a  clean  linen  or 
cotton  rag,  and  is  afterwards  allowed  to  dry  in  the  air,  or  at  a  good  distance 
from  the  fire ;  when  dry  a  gloss  is  given  with  a  clean  brush  on  which  a  minute 
drop  of  oil  is  first  applied. 

It  is  better  to  do  too  little  polishing  at  first,  so  as  to  need  a  repetition  of 
the  process,  rather  than  by  injudicious  activity,  to  round  and  obliterate  all 
the  delicate  points  and  edges  of  the  works,  upon  the  preservation  of  which 
their  beauty  mainly  depends. 


FLAT  AND  FILED  WORKS. 

4. — SUPERIOR  FLAT  WORKS  are  accurately  filed  and  scraped,  then  cleaned  with  fine 
glass  paper  folded  around  a  square  stick,  afterwards  with  whiting  also  on  a 
stick  of  deal  planed  very  flat  and  square  and  used  as  a  file  ;  some  workmen 
cover  the  wood  with  one  or  two  layers  of  flannel  or  cloth,  but  the  naked 
wood,  although  somewhat  tedious,  will  produce  more  exact  surfaces  and 
better  defined  edges. 


1069        DESCRIPTIVE    CATALOGUE    OP    APPARATUS,    MATERIALS, 

5. — COMMON  FILED  AND  CARVED  WORKS  are  finished — 1st,  with  Trent  sand  and 
water  on  flannel  or  a  brush ;  2ndly,  scraped  Flanders  brick  used  in  the  like 
manner  ;  3rdly,  wet  linen  or  woollen  rag  with  powdered  chalk,  which  soon 
rubs  down  smooth,  and  to  the  condition  of  ordinary  whiting. 

6. — RAZORS  AND  KNIFE  HANDLES  are  most  generally  finished  by  shaving  or  scrap- 
ing, and  2ndly  by  buffing  them  on  the  wheels,  as  more  fully  explained  under 
the  head  TORTOISESHELL  ;  but  the  following  methods  are  by  some  preferred. 

7. — COMMON  RAZOR  HANDLES. — These  are  sawn  out  and  filed,  then  scraped  with  an 
old  razor  blade,  called  a  shaving  blade ;  two  razor  handles  or  scales  are  then 
held  at  the  one  end  in  a  pair  of  clamps  in  the  vice,  and  rubbed  lengthways — • 
1st,  with  chalk  and  water  on  felt  or  cloth,  which  cuts  very  quickly  ;  and  2ndly 
with  whiting  and  water  for  the  finish. 

8. — BEST  RAZOR  HANDLES. — Two  scales  are  slightly  rivetted  together  and  buffed, 
1st,  on  a  buff  wheel  fed  with  Trent  sand  ;  2ndly,  buffed  with  rottenstone  ; 
3rdly,  they  are  handed  up  or  polished  with  the  naked  hand  and  rotten- 
stone.  Other  workmen  entirely  omit  the  rottenstone,  which  requires  oil,  and 
conduct  the  work  with  chalk  and  whiting,  so  that  water  may  be  used  through- 
out the  work. 

9. — UMBRELLA  AND  PARASOL  HANDLES,  and  many  similar  pieces  are  polished  first 
with  sand,  and  then  with  whiting,  on  cloth  wheels  consisting  of  several  circles 
of  thick  cloth  or  felt,  clamped  between  two  smaller  disks  of  wood  ;  the  cloth 
projects  about  an  inch  around  the  margin  to  make  a  soft  elastic  edge. 

JACINTH  or  Hyacinth.— See  ZIRCON. 

JADE  is  polished  by  lapidaries  like  CARNELIAN  but  it  only  takes  a  greasy  and  not 
a  brilliant  polish. 

JAPANNED  WORKS.— Such  of  the  japanned  works  as  are  baked  hi  ovens,  for  the 
evaporation  of  the  solvent  of  the  varnish,  are  1st  forwarded  with  pumice- 
stone  powder  applied  with  water  on  list  or  flannel  ;  2ndly  they  are  polished 
either  with  rottenstone  or  putty  powder  and  oil,  also  on  flannel ;  and  3rdly 
with  the  dry  hand  and  rottenstone. 

JARGOON.— See  ZIRCON. 

JASPER  obtains  just  the  same  treatment  as  Camelian  in  the  Lapidary's  art ;  it 
occurs  of  numerous  colours  and  varieties,  and  is  nearly  equal  to  Agate  in 
point  of  hardness. 

JET  is  a  soft  bituminous  mineral,  and,  like  Cannel  Coal,  receives  in  the  hands  of  the 
lapidary  the  same  routine  as  ALABASTER  ;  which  see. 

The  articles  on  Jet  and  Cannel  Coal  (vol  1,  page  162  —  3)  describe  an  en- 
tirely different  method  of  working  these  peculiar  substances,  and  to  which  the 
reader  is  referred.  See  also  CANNEL  COAL  in  this  Catalogue. 


AND    PROCESSES    FOR    GRINDING    AND    POLISHING.  1070 

JEWELLERY. — See  the  articles  on  Gold,  Silver,  Enamels,  and  Saw-dust. 

LAC  or  GUM  LAC  is  used  in  India  with  powdered  corundum  in  the  formation  of 
wheels  and  rubbers  ;  see  CORUNDUM.  It  is  somewhat  used  in  the  same 
manner  hi  England,  but  with  emery  instead  of  corundum. 

LAPIS  LAZULI  "  is  used  in  jewellery,  but  is  chiefly  important  as  affording  that 
beautiful  pigment  ultra-marine,  so  highly  valued  by  painters  on  account  of  its 
great  advantage  in  not  changing  by  time  or  exposure." — In  producing  this 
pigment  the  mineral  is  simply  calcined  and  then  levigated.  The  lapis  lazuli  is 
difficult  to  polish  on  account  of  the  irregularity  of  its  substance,  which 
abounds  in  soft  parts  that  wear  away  more  quickly  than  the  remainder  ;  it  is 
treated  as  CABNELIAN. 

iPS,  metal  polishing  wheels,  see  WHEELS,  articles  37  to  47.  . j| 

jAVAS,  which  are  occasionally  arranged  as  specimens,  do  not  in  general  admit  of 
being  well  polished,  because  of  their  being  irregularly  hard  and  soft,  and  also 
scoriacious  ;  they  are  worked  by  the  lapidary  just  like  ALABASTER,  which  see. 

LEAD  is  the  basis  of  many  of  the  laps,  and  is  rendered  sometimes  harder  by  the 
addition  of  variable  proportions  of  tin  and  antimony  ;  see  WHEELS,  articles, 
37  to  47. 

Lead  may  be  readily  worked  with  rasps,  but  it  clogs  files  so  much  as  to 
render  it  difficult  to  produce  a  smooth  surface  by  those  instruments ;  in 
practice  it  is  generally  scraped  for  the  smoothest  surfaces.  Lead  is  not 
often  polished,  it  would  require  to  be  treated  like  pewter  but  with  greater 
care,  to  prevent  the  formation  of  utters  in  the  scraping  or  burnishing. 

Lead  when  reduced  to  the  white  oxide,  forms  the  commonest  kind  of 
putty  powder,  the  process  of  manufacturing  which  is  described  under  the 
head  PUTTY  POWDER. 

LEATHER. — The  leather  principally  used  for  polishing,  hi  the  manufacturing 
towns  of  Sheffield  and  Birmingham,  is  the  beast  hide,  or  the  leather  of 
the  ox  as  prepared  for  the  soles  of  shoes,  which  is  much  softer  and  open  in 
the  grain  before  it  is  hammered  as  for  the  soles  of  shoes.  The  hide  is  usually 
cut  into  parallel  pieces  or  strips,  which  are  glued  around  the  edges  of  wooden 
disks  ;  then  constituting  buff  wheels  if  charged  with  emery,  and  polishers  if 
dressed  with  crocus ;  and  the  leather  is  also  fixed  on  straight  sticks  known  as 
buff  sticks. 

The  leather  varies  much  hi  thickness,  that  about  the  neck  of  the  hide  being 
sometimes  nearly  an  inch  thick,  and  very  soft,  this  part  being  designated  as 
bull  neck,  a  material  for  which  the  thick  hide  of  the  sea  cow  or  sea  horse  ia 
frequently  substituted. 

Occasionally  the  curried  hides  of  the  horse,  and  other  leathers  used  in 
making  harness,  are  employed  for  buff  wheels ;  and  in  the  metropolis  in 


1071         DESCRIPTIVE    CATALOGUE    OF    APPARATUS,    MATERIALS, 

particular,  the  thick  buff  leather  of  old  regimental  belts  is  much  employed 
for  similar  uses,  but  although  cheaper  it  is  softer  and  far  less  durable. 
Wash  leather,  prepared  from  sheep  skins  split  in  two,  is  also  much  used  in 
polishing,  but  mostly  after  the  manner  of  a  dusting  cloth,  or  to  prevent  the 
hand  touching  the  goods. 

LENSES.— fife*  Chap.  XXXIII.    Sect.  4. 

LIME  is  occasionally  used  as  a  polishing  material  on  account  of  its  cheapness,  as 
the  only  preparation  required  is  to  slake  the  lime  with  a  little  water,  it  then 
falls  to  a  fine  powder  and  which  is  sometimes  sifted.  Lime  is  used  for 
polishing  the  commonest  works  in  bone,  such  as  brushes,  and  also  for  Albata 
Spoons. 

LIMESTONES. — The  substances  to  which  this  name  is  applied  differ  greatly  in 
hardness  and  compactness.  Some  are  so  soft  as  not  to  admit  of  being 
polished,  and  are  treated  much  the  same  as  the  Freestones,  (which  see,) 
whereas,  those  limestones  which  do  admit  of  being  polished,  are  generally 
designated  under  the  name  marble,  the  mode  of  polishing  which  is  minutely 
described  under  that  head. 

LITHOGRAPHIC  STONES,  are  a  fine  oolite,  a  peculiar  kind  of  fine  granular  lime- 
stone, principally  obtained  from  the  interior  of  Germany. 

The  surfaces  of  lithographic  stones  are  required  to  possess  different  degrees 
of  smoothness,  according  to  the  subject  for  which  they  are  employed.  When 
the  drawing  is  to  be  made  at  once  upon  the  stone,  a  certain  amount  of  rough- 
ness or  granulation  is  necessary,  or  it  will  not  so  well  abrade  the  lithographic 
drawing  chalk,  and  this  granulation  is  required  to  be  more  or  less  fine 
according  to  the  kind  of  drawing.  But  much  smoother  surfaces  are  required 
for  those  stones  upon  which  the  transfer  process  is  to  be  employed,  as  for 
lithographic  writing,  which  is  first  executed  on  paper,  and  then  transferred 
to  the  stone,  by  passing  them  together  through  the  press. 

The  stones  are,  1st,  rubbed  smooth  with  another  lump  of  lithographic  stone, 
and  silver  sand  applied  with  water,  the  sand  is  prepared  of  different  degrees 
of  fineness  by  sifting,  as  explained  under  the  head  Emery,  the  coarsest  sieves 
employed  have  about  80  wires  in  the  inch,  the  finest  about  120.  The  stones 
for  chalk  drawing  are  left  from  the  sand  of  appropriate  fineness,  but  those 
required  for  the  transfer  process  are,  2ndly,  smoothed  with  a  lump  of  pumice- 
stone  and  water,  and  3rdly,  polished  with  a  piece  of  snake  stone,  also  applied 
with  water. 

LOAM  is  used  with  water  by  some  manufacturers  as  a  cheap  material  with  which 
to  grind  in  the  conical  plugs  of  brass  valves  and  cocks.  Loam  contains 
more  silex  than  the  generality  of  the  clays,  but  which  also  are  occasionally 
used  for  polishing  common  works. 


AND    PROCESSES    FOR    GRINDING    AND    POLISHING. 


1072 


MACHINERY  COMPOSED  OF  WROUGHT-!RON,  CAST-IRON  AND  STEEL.— The  engineer 
and  mechanist  employ  nearly  the  same  routine  for  polishing  these  three 
materials,  more  particularly  in  turned  works,  in  which  the  variations  prin- 
cipally depend  upon  the  degree  of  finish  required.  This  general  article  is 
therefore  intended  to  apply  to  each  of  the  three  materials  ;  and  some  parti- 
cular observations  expressly  suited  to  each  of  them,  will  be  found  under  their 
respective  heads  of  WROUGHT-!RON,  CAST-IRON,  and  STEEL. 


TURNED  WORKS. 

1 . — LARGE  SIZED  TURNED  WORKS. — Such  parts  of  machinery  as  come  under  this 
denomination,  are  in  almost  every  case  turned  in  self-acting  lathes,  which, 
under  proper  management,  leave  the  surfaces  very  exact  and  smooth,  so 
that  many  of  them  require  no  polishing  whatever ;  and  which  process  is 
reserved  for  those  exterior  parts  which  meet  the  eye,  when  the  machinery 
is  erected. 

Heavy  works  are  made  to  revolve  with  considerably  greater  velocity  than 
that  proper  for  turning,  and  they  are  polished  with  a  long  stick  of  deal  1  to 
2  inches  thick,  and  2  to  4  inches  wide,  the  end  of  which  is  cut  off  square. 
The  stick  is  dipped  into  a  shallow  vessel  containing  oil,  then  into  another 
with  dry  emery  after  which  it  is  pressed  forcibly  against  the  work,  never 
being  allowed  to  remain  long  hi  one  position  upon  the  lathe  rest.  Occa- 
sionally, for  additional  purchase,  a  bent  bar  of  iron  is  used,  to  the  end  of 
which  is  fixed  a  block  of  wood,  in  imitation  of  the  hanging  tools  for  turning 
iron,  figs.  423  and  424,  page  527,  vol.  ii.  Sometimes  on  the  end  of  the  polishing 
stick  is  placed  a  thick  piece  of  leather  for  the  application  of  the  emery,  of 
which  two  or  at  most  three  different-sized  grains  are  used,  namely,  corn 
emery,  grinding,  and  fine  grinding  emery. 

2. — MEDIUM  SIZED  TURNED  WORKS. — Many  of  these  which  are  turned  in  power 
lathes  running  at  a  proportionate  velocity,  with  tools  properly  formed  and 
lubricated  with  abundance  of  water  from  a  small  jet,  are  left  so  smooth  as 
hardly  to  want  any  polishing,  or  at  most  an  inconsiderable  amount  of 
polishing  with  fine  emery  powder  or  emery  paper  ;  but  in  other  works  less 
skilfully  turned  by  hand  tools  and  with  little  or  no  water,  it  is  usual  to 
reduce  any  very  trifling  irregularities  of  surface  to  a  general  level,  by  means 
of  a  smooth  file,  slightly  greased,  which  is  rubbed  lightly  over  the  work  as 
it  revolves  ;  careless  workmen  are  apt  however  to  rely  too  much  on  this 
practice,  and  having  left  the  work  full  of  ridges  from  the  turning  tool,  to 
begin  with  a  coarse  file  ;  this  practice  is  detrimental  to  the  production  of 
good  true  work,  and  the  preservation  of  the  angles. 

Works  of  medium  size  are  polished  nearly  as  above  described,  but  with 
a  deal  stick  chopped  to  a  chisel  edge,  or  to  a  square  point  and  thrust 
against  the  work  ;  sometimes  instead  of  the  point  the  side  of  the  stick 
near  the  end  is  used  as  a  crow-bar  for  additional  purchase. 

Generally  two,  but  occasionally  three  sizes  of  emery  are  used,  varying 


1073        DESCRIPTIVE    CATALOGUE    OF    APPARATUS,    MATERIALS, 

from  grinding  to  flour  emery  ;  but  it  is  necessary  between  the  application  of 
each  powder,  to  wipe  the  work  entirely  clean,  with  rags,  cotton-waste,  saw- 
dust, nioslings,  (or  the  curriers'  shavings  of  leather),  and  also  to  use  a  fresh 
stick,  or  to  chop  a  clean  point,  for  every  kind  of  emery. 

3. — SMALL  SIZED  TURNED  WORKS. — For  these,  emery  sticks,  (those  with  emery 
glued  upon  them,)  and  emery  paper  are  much  used  ;  but  the  loose  powder 
applied  as  above  although  less  cleanly,  is  in  general  somewhat  quicker  and 
also  cheaper.  For  the  plane  surfaces  and  other  parts  of  small-turned  works, 
required  to  be  particularly  flat,  emery  paper  folded  around  a  smooth  file  or 
a  flat  piece  of  wood  is  used,  or  else  flat  pieces  of  mahogany,  box- wood  or 
metal,  supplied  with  fine  emery  powder  and  oil  are  employed  with  still 
greater  advantage. 

In  some  few  cases  after  the  finest  or  flour  emery  has  been  used,  fine 
crocus  is  applied  similarly,  or  with  a  buff  stick,  but  this  is  unusual  as  two 
sizes  of  emery  are  alone  in  general  employed.  Some  parts  of  superior 
works  in  iron  and  steel,  especially  the  rounded  edges,  are  brightened  with 
the  burnisher,  but  such  parts  require  to  be  previously  polished  quite  smooth ; 
both  the  work  and  burnisher  must  be  wiped  thoroughly  clean  from  emery  or 
dust,  the  burnisher  is  then  held  against  the  work  as  it  revolves,  a  little  oil 
being  interposed  to  lubricate  the  surfaces. 

4. — SCREW  THREADS  that  are  required  to  fit  accurately  and  smoothly,  and  also  to 
sustain  frequent  unscrewing,  should  be  polished  with  a  pointed  stick  and 
emery  ;  as  frequently  the  removal  of  the  rough  edges  will  make  that  screw 
enter  which  appeared  to  be  too  large,  and  the  smooth  screw  present  far  less 
friction  and  disposition  to  wear  out. 

5, — THE  HEADS  OF  SCREWS  are  often  finished  with  the  side  of  an  emery  stick 
as  they  revolve  in  the  lathe  ;  and  if  they  are  to  be  burnished  the  emery 
must  be  carefully  removed  from  the  notch  by  folding  the  rag  and  drawing 
it  through  like  a  saw  or  the  process  will  fail,  and  the  burnisher  will  be 
injured. 

6. — SMALL  ROUND  RODS  used  for  inferior  purposes  and  not  requii'ing  to  be 
cylindrical,  are  often  ground  bright  against  the  edges  of  large  revolving 
grindstones  driven  by  power.  The  rod  is  held  rather  loosely  in  the  hands 
of  the  workman  and  at  a  small  angle  to  the  axis  of  the  stone  ;  then  without 
any  great  attention  on  the  part  of  the  individual,  the  grindstone  causes  the 
rod  slowly  to  rotate  in  his  hands,  so  as  to  act  on  every  part  of  its  circum- 
ference, and  the  obliquity  of  the  two  axes  also  causes  the  rod  to  traverse 
endlong  through  the  hands  like  a  screw,  and  thus  every  part  of  the  rod  is 
acted  upon  successively  by  the  grindstone. 

7. — CYLINDRICAL  WORKS  that  require  great  accuracy  are  ground  by  methods  that 
will  be  explained  in  Chap.  XXXIII.  Sect.  2,  but  other  cylindrical  rods  of 
inferior  kinds,  used  only  as  levers  and  for  similar  common  purposes,  are  often 
polished  between  two  sticks,  (supplied  with  emery  and  oil,)  placed  trans- 
versely to  the  cylinder,  grasped  in  both  hands,  and  rubbed  lengthways  on 
the  work  as  the  lathe  revolves.  Considerable  friction  may  thus  be  given  "on 


AND    PROCESSES    FOR    GRINDING    AND    POLISHING.  1074 

opposite  sides,  and  therefore  without  bending  the  cylinder,  the  figure  of 
which  is  materially  improved  by  the  treatment.  Sometimes  for  greater 
purchase,  the  sticks  are  united  at  the  one  end  by  a  loop  of  string  or  wire, 
and  compressed  at  the  other,  like  nut-crackers,  with  one  or  both  hands. 
8. — LATHES  FOB  POLISHING. — In  large  manufactories  it  is  usual  to  perform  the 
polishing  on  common  lathes  kept  entirely  apart  from  those  used  for 
turning,  on  account  of  the  mischief  that  ensues  when  gritty  matters  find 
their  way  into  the  fittings  of  the  mandrel  or  other  part  of  the  lathe  ;  and 
careful  workmen  who  use  the  same  lathe  for  turning  and  also  for  polishing, 
avoid  with  scrupulous  care  the  scattering  of  the  powders,  and  frequently 
employ  a  spare  center  for  the  popit  head,  in  polishing  spindles  and  pieces 
requiring  support  at  both  ends,  as  the  grit  is  almost  sure  to  deteriorate  the 
center  employed  in  polishing  works. 

FLAT  WORKS. 

9. — LARGE-SIZED  FLAT  WORKS. — These  are  in  almost  every  case,  castings  in 
iron,  wrought  in  the  planing  machine  ; — a  machine  that  produces  its  results 
with  so  much  accuracy  and  precision,  that  polishing  is  not  frequently 
required  as  the  concluding  step.  When  however  large  planed  works  are 
polished,  it  is  with  rubbers  of  various  kinds  applied  with  emery  and  oil. 
Sometimes  a  flat  lump  of  lead  is  cast  upon  the  center  of  an  old  file,  or  of  a 
still  longer  bar  of  iron  ;  at  other  times  a  bar  of  wood  serves  as  the  handle, 
and  to  it  is  fixed  by  screws  or  nails  a  piece  of  lead  or  wood,  or  wood  covered 
with  thick  leather  ;  such  rubbers  are  generally  held  in  the  two  hands  much 
after  the  manner  of  the  spokeshave  or  drawknife,  or  they  are  worked  by  one 
very  long  handle  as  in  smoothing  a  large  slab  of  stone  or  marble.  When 
the  rubbers  are  large  they  are  occasionally  loaded  with  heavy  weights,  so 
that  the  workmen  have  only  to  drag  them  to  and  fro  on  the  works,  the  forms 
of  which  latter  are  in  general  too  diversified  to  offer  much  inducement  to 
the  application  of  machinery  to  rectilinear  polishing. 

1 0. — MEDIUM-SIZED  FLAT  WORKS. — Such  of  these  as  are  of  cast-iron,  are  also 
for  the  most  part  worked  in  the  planing  machine,  and  if  at  all  polished,  it  is 
done  with  emery  rubbers  nearly  or  precisely  as  above  described  ;  most  of 
the  flat  parts  of  mechanism  that  are  made  in  wrought  iron  and  steel,  are  too 
irregular  in  their  forms  to  admit  of  being  worked  otherwise  than  with  the 
file.  The  black  oxidized  surfaces  of  forged  works  are  often  removed  on 
the  grindstone  prior  to  the  application  of  the  file  ;  this  application  of  the 
grindstone  is  in  general  highly  economical,  it  being  comparatively,  much 
more  rapid  in  its  action,  and  less  costly  in  respect  to  wear  and  tear  than 
the  file. 

Sometimes,  indeed,  the  flat  parts  of  iron  works  are  reduced  on  the  grind- 
stone to  accurate  plane  surfaces,  but  this  requires  the  assistance  of  mechanism, 
which  is  by  no  means  common ;  this  subject,  and  also  the  application  of 
revolving  metallic  laps  to  the  production  of  flat  works,  will  be  noticed  in  the 
first  section  of  Chap.  XXXIII. 


1075         DESCRIPTIVE   CATALOGUE    OF    APPARATUS,  MATERIALS, 


The  coarser  and  larger  of  the  filed  works  are  sometimes  left  from  the  file, 
or  without  being  subsequently  polished  ;  in  which  case  the  coarser  marks 
left  from  the  file  when  used  in  the  customary  manner,  or  from  point  to  heel, 
are  removed  by  the  method  known  as  draw-filing,  in  which  the  file  is  drawn 
sideways  along  the  work  ;  draw-filing  is  particularly  employed  in  narrow 
pieces.  Large  broad  surfaces  are  occasionally  finished  by  giving  a  circulating 
motion  to  the  file,  thereby  producing  curly  marks.  Each  of  these  latter  pro- 
cesses are  more  effectual  when  the  file  is  moderately  supplied  with  oil, 
which  lessens  its  disposition  to  become  pinny,  or  clogged,  by  particles  which 
stick  into  it,  and  scratch  the  work  ;  but  the  reader  is  referred  to  the  pre- 
vious chapter  on  the  File,  vol.  ii.,  page  852,  for  more  detailed  particulars  of 
these  applications  of  this  useful  instrument. 

Works  requiring  a  finish  superior  to  that  of  draw-filing,  are  rubbed  with  an 
emery  stick,  or  with  rubbers  of  the  various  kinds  already  noticed,  and  supplied 
with  emery  and  oil. 

11. — SMALL-SIZED  FLAT  WORKS,  after  having  been  draw-filed,  are  more  usually 
finished  with  the  emery  stick,  and  often  followed  by  emery  paper  of  different 
degrees  of  coarseness  wrapped  on  a  file  or  a  square  stick.  The  emery  is 
moistened  with  oil  for  the  more  finished  works,  the  dry  rubber  gives  however 
the  brighter  surface,  and  it  is  sometimes  applied  with  a  curling  motion,  so  as 
to  diversify  the  grain  left  on  the  work. 

Buff  sticks  supplied  with  crocus  are  often  used  for  the  last  gloss,  but  on 
small  flat  surfaces  they  must  be  cautiously  applied  for  fear  of  rounding  them, 
a  defect  that  is  easily  distinguished,  and  very  objectionable. 

Still  smaller  works  and  those  required  to  be  very  flat  are  finished  with 
square  slips  of  stone  with  oil,  or  slips  of  mahogany,  brass  or  tin,  any  of  which 
are  used  with  fine  flour  emery  or  oilstone-  powder  and  then  with  crocus. 

12. — SMALL  FLAT  WORKS  OF  HARDENED  STEEL. — As  it  commonly  happens  that  in 
the  process  of  hardening  steel  works  they  are  more  or  less  distorted  from 
their  intended  figures,  and  as  in  many  cases  it  is  impossible  or  inadmissible 
to  restore  them  to  the  plane  figure  by  the  hack  hammer,  (see  vol.  1 ,  p.  247,) 
grinding  is  then  resorted  to,  metal  laps  generally  of  lead  with  a  little  anti- 
mony, and  laps  of  copper  or  of  cast-iron  are  also  employed  with  emery  and 
water.  When  it  is  desired  the  works  should  present  very  true  plane  surfaces, 
the  laps  should  be  themselves  very  exact  and  flat.  There  is  however  a  con- 
stant tendency  to  depreciate  the  figure  of  the  lap,  because  the  outer  part  or 
exterior  diameter  gets  the  more  worn,  on  account  of  the  greater  rapidity  of 
its  action  at  that  part.  After  the  lap  has  been  used,  the  mode  of  finishing 
described  in  the  last  article  is  also  sometimes  employed. 

13. — WATCHWORKS  IN  STEEL.— Steel  works  of  this  diminutive  kind  are  generally 
polished  by  the  watchmakers,  1st  with  a  steel  rubber  and  oilstone  powder, 
2ndly,  with  a  steel  rubber  and  crocus  of  two  degrees  of  coarseness,  which  is 
frequently  called  red  stuff  from  its  colour,  and  Srdly  with  gun  metal  or  glass 
rubbers  supplied  with  fine  crocus. 
Some  of  the  work  is  beautifully  finished  on  tin  or  pewter  revolving  laps, 


AND    PROCESSES    FOR    GRINDING    AND    POLISHING.  1076 

into  which  the  red  stuff  is  embedded,  occasionally  with  the  burnisher,  they 
are  used  nearly  or  quite  dry,  and  when  the  laps  are  carefully  preserved,  they 
themselves  present,  under  the  magnifier,  a  beautiful  smooth  surface  and 
which  they  impart  to  the  work. 

Many  of  the  grinders  and  rubbers  for  watchwork,  are  made  from  one  to 
two  inches  square,  and  of  steel,  glass,  gun-metal,  tortoiseshell,  horn,  or  ivory, 
&c.,  the  small  pieces  are  laid  down  upon  the  anointed  grinders,  and  rubbed 
about  with  the  fingers,  as  if  the  work  were  a  muller  used  in  grinding  paint, 
this  mode  also  preserves  the  flatness  of  the  respective  objects  in  a  most 
admirable  manner. 

MALACHITE,  or  the  massive  green  carbonate  of  copper,  is  much  used  for  jewellery 
and  articles  of  vertu,  the  finest  malachite  is  from  Russia,  and  as  it  is  traversed 
by  numerous  circular  fissures  ;  from  the  imperfect  joinings  of  the  botryoidal 
masses  of  which  it  may  be  considered  to  be  composed ;  it  is  difficult  to  polish, 
and  requires  great  care  and  attention  ;  notwithstanding  its  hardness  it  is  con- 
sidered by  some  lapidaries  better  to  treat  it  as  alabaster  than  carnelian,  but 
each  method  is  followed. 

[  ARBLE  is  polished  in  different  modes,  which  are  jointly  dependent  on  the  nature 
of  the  marble,  and  the  character  of  the  work;  some  of  the  principal  methods 
will  be  described. 

Marble  is  generally  worked  by  the  lapidary  after  the  manner  of  carnelian, 
sometimes  of  alabaster,  but  he  is  far  less  successful  in  this  department  of  art 
than  the  sculptor  and  marble  workers. 

1 . — MARBLE  ORNAMENTS  and  small  works  intended  for  close  inspection,  and  which 
require  the  highest  possible  finish. — "  After  the  marble  is  sawn  into  slab  the 
first  operation  is  to  grind  it  down  with  a  flat  coarse  sand-stone  and  water, 
or  with  an  iron  plate,  fed  with  fine  sand  and  water,  until  all  the  marks  of 
the  saw  are  perfectly  removed  ;  2ndly,  a  fine  sandstone,  (procured  from 
Bilston,)  is  used  with  water,  until  the  marks  made  by  the  first  stone  are 
removed  ;  3rdly,  a  finer  sandstone  which  is  found  near  Congleton,  is  applied 
to  work  out  the  marks  of  the  former  ;  4thly,  pumice-stone  with  water,  and 
5thly,  snake  stone  is  used,  and  the  last  finishes  what  is  called  the  growiding. 

"  Next  comes  the  polishing,  which  is  principally  performed  with  rollers  of 
woollen  cloth  or  list  made  to  the  size  of  about  three  inches  diameter.  As 
the  6th  process  a  rubber  is  charged  with  flour  emery  and  a  moderate  degree 
of  moisture  ;  this  rubber  is  worked  uniformly  over  every  part,  until  the 
marble  acquires  a  kind  of  greasy  polish  ;  7thly,  the  work  is  completed  with 
a  similar  roll  of  cloth  charged  with  putty  powder  and  water.  Some  prefer 
as  the  polisher,  an  old  cotton  stocking  not  made  into  a  rubber,  and  in  some 
few  of  the  more  delicate  works,  crocus  is  used  intermediately  between  the 
emery  and  the  putty-powder.  It  is  necessary  to  wash  the  marble  after  each 
operation,  so  that  not  a  particle  of  the  previous  polishing  material  may 
remain,  otherwise  the  work  will  be  scratched." 

E2 


1077        DESCRIPTIVE    CATALOGUE    OF    APPARATUS,    MATERIALS, 

2.— MARBLE  WORKS  TURNED  IN  THE  LATHE. — "  Turned  works  are  polished  as 
above,  excepting  that  for  the  rolls  of  cloth  are  substituted  two  or  three 
thicknesses  of  cloth  supplied  with  emery  or  putty  powder,  and  held  upon 
the  work  by  the  hand,  which  is  constantly  moved  about." 

For  the  above  paragraphs,  and  also  for  the  practical  remarks  on  turning 
marble,  the  author  is  indebted  to  Mr.  Hall  of  the  Marble-works,  Derby  ; 
and  for  the  subsequent  particulars  to  Mr.  Thomas  Smith,  sculptor,  of  London. 
3.— STATUARY  and  large  works  in  marble,  which  are  dependent  on  their  general 
design  and  effect,  rather  than  on  elaborate  finish,  are  executed  by  a  different 
class  of  artists,  and  require  only  part  of  the  above  proceses  to  be  resorted 
to.  By  Statuaries  the  marble  is  rubbed  with  two  qualities  of  gritstone,  the 
coarse,  which  is  somewhat  finer  than  Bilston,  is  known  as  first  grit,  and  the  fine 
as  second  grit.  Thirdly,  the  work  is  smoothed  with  snakestone,  after  which  the 
white  or  statuary  marble  is  finished  with  putty  powder  and  water,  on  a  wooden 
Uock  covered  with  thick  nap,  or  felted  cloth.  (See  article  RUBBER.) 

The  Irish  black  marble  is  by  some  considered  harder  than  the  Derbyshire, 
and  after  the  snakestone  has  been  used,  it  is  polished  with  tripoli  on  felt  as 
above,  and  finished  with  putty  powder  or  crocus,  but  the  rubber  is  then 
covered  with  three  thicknesses  of  stout  linen. 

The  finest  Welsh  black  marble  is  esteemed  still  harder  and  blacker  than 
the  Irish,  and  after  the  snakestone,  is  polished  by  laying  a  thin  plate  of 
copper  or  lead  on  the  wooden  rubber,  and  using  therewith  tripoli  and  water, 
and  finally  putty  powder  or  crocus  on  linen  as  before. 

The  Irish  marble  is  less  brittle  than  the  Welsh,  and  better  suited  to 
carved  ornaments.  Marble  has  of  late  years  been  sawn,  ground,  and 
polished  to  a  very  great  extent,  by  means  of  machinery,  much  of  which  took 
its  rise  from  the  comparatively  old  machinery  used  for  the  same  purposes  in 
Derbyshire. 

SCULPTURE. — The  dull  parts  of  sculpture  are  finished  in  four  different  manners, 
or  rather,  the  complete  process  of  smoothing  is  discontinued  at  various 
stages,  so  as  to  form  four  gradations,  denoted  by  the  respective  paragraphs. 

The  marble  is  First,  sometimes  left  from  the  long  and  very  slender  statu- 
ary's chisel,  the  reverse  end  of  which  is  formed  with  a  sharp  circular  edge  or 
ridge,  just  like  a  hollow  center,  in  order  that  the  metal  hammer,  which  is  of 
soft  iron,  tin,  or  zinc,  may  be  slightly  indented  by  the  chisel,  so  as  to  avoid 
its  glancing  off ;  the  chisel  marks  leave  the  surface  somewhat  rough  and 
matted,  intermediate  between  the  granular  and  crystalline  character. 

Secondly,  For  surfaces  somewhat  smoother,  rasps  are  used  to  remove  the 
ridges  left  by  the  chisel,  the  rasps  leave  a  striated  or  lined  effect  suitable  for 
draperies,  and  which  is  made  more  or  less  regular  according  to  the  uniformity 
of  the  strokes,  or  the  reverse. 

Thirdly,  Files  are  employed  for  still  smoother  surfaces  of  the  same 
character  ;  and  it  is  to  be  observed  that  the  files  and  rasps  are  generally 
curved  at  the  ends,  to  adapt  them  to  the  curvilinear  forms  of  the  sculpture. 
See  the  article  on  RIFLERS,  in  the  chapter  on  FILES,  vol.  2,  page  834. 


AND    PROCESSES    FOR    GRINDING    AND    POLISHING.  1078 

Fourthly,  For  the  smoothest  of  the  dull  or  unpolished  surfaces,  the  faint 
marks  left  by  the  file  are  rubbed  out  with  Trent  sand  or  silver  sand  and 
water,  applied  by  means  of  a  stick  of  deal  cut  to  a  point,  and  rubbed  all  over 
the  work  in  little  irregular  circles,  as  a  child  would  scribble  on  a  slate,  and 
if  the  end  of  the  stick  is  covered  with  two  or  three  thicknesses  of  cloth, 
the  marble  receives  a  still  rounder  or  softer  effect  than  from  the  naked 
stick,  for  which  the  cabbage  wood  or  partridge  wood  is  sometimes  used, 
and  the  end  of  the  stick  is  slightly  bruised,  so  that  the  fibres  of  the  wood 
may  assume  the  character  of  the  stiff  brush,  known  by  artists  as  a  scrub. 

Mr.  Thomas  Smith  adds  that  he  has  successfully  copied  the  minute  rough- 
ness or  granulation  of  the  skin,  by  a  kind  of  etching  which  lie  was  induced 
to  try,  by  imagining  that  he  could  trace  such  a  process  to  have  been  used 
in  some  of  the  most  perfect  of  the  ancient  marbles  that  had  not  been 
exposed  to  open  air.  The  work  having  been  smoothed  with  sand  as  above, 
he  takes  a  hard  stubby  brush,  and  therewith  dots  the  marble  with  muriatic 
acid,  and  which  quickly,  yet  partially,  dissolves  the  surface.  The  stringency 
of  the  acid,  which  must  not  be  excessive,  is  tested  upon  a  piece  of  waste 
marble  :  the  brush  is  hastily  dipped  in  the  acid,  applied  to  the  work,  quickly 
rinsed  in  water,  and  then  used  for  removing  the  acid  from  the  marble. 
It  is  obvious  the  process  calls  for  a  certain  admixture  of  dexterity  and  bold- 
ness, and  sometimes  requires  several  repetitions,  the  process  occupying  only 
a  few  minutes  each  time. 

Fifthly,  The  bright  parts  of  sculpture.  Few  of  the  works  in  sculpture 
are  polished,  and  such  as  are,  are  required  in  the  first  instance  to  pass 
through  the  four  stages  already  explained  for  producing  the  smooth  but 
dull  surface  ;  after  which,  slender  square  pieces  of  the  second  gritstone 
and  of  snakestone  are  used  with  water  as  a  pencil,  and  then  fine  emery  and 
putty  powder  on  sticks  of  wood  ;  but  the  work  is  exceedingly  tedious,  and 
requires  very  great  care,  that  the  artistical  character  of  the  work,  and  any 
keen  edges  that  may  be  required  are  not  lost  in  the  polishing.  To  avoid 
the  tediousness  and  the  risk  of  deterioration,  it  is  not  unusual  in  carved 
black  marbles,  and  those  of  dark  colours,  after  using  the  snakestone,  to  coat 
the  work  with  varnish,  by  which  a  gloss  is  given  without  attrition.  The 
pillars  of  the  Temple  Church,  London,  which  are  of  Durbec  marble,  were  in 
like  manner  French  polished,  after  the  manner  of  furniture,  when  that 
building  was  recently  restored. 

MARBLES  FOR  CHILDREN.— These  are  principally  manufactured  in  Germany  ; 
some  are  made  of  clay  covered  with  a  glaze  and  baked  as  in  pottery  ;  others 
are  made  of  alabaster  and  marble  ;  but  the  greater  part  are  made  of  a  hard 
stone  found  near  Coburg  in  Saxony.  The  stone  is  first  broken  with  the 
hammer  into  small  cubical  fragments,  and  about  100  to  150  of  these  are 
ground  at  one  time  in  a  mill,  somewhat  like  a  flour  mill.  The  lower  stone, 
and  which  remains  at  rest,  has  several  concentric  circular  grooves  or  furrows ; 
the  upper  stone  is  of  the  same  diameter  as  the  lower,  and  is  made  to  revolve 

* 


1079         DESCRIPTIVE    CATALOGUE    OF    APPARATUS,  MATERIALS, 

by  water  or  other  power.  Minute  streams  of  water  are  directed  into  the 
furrows  of  the  lower  stone.  The  pressure  of  the  runner  on  the  little  pieces 
rolls  them  over  in  all  directions,  and  in  about  one  quarter  of  an  hour  the 
whole  of  the  rough  fragments  are  reduced  into  nearly  accurate  spheres. 
Frequently  a  thick  circular  slab  of  oak  or  elm  is  used  instead  of  the  upper  or 
revolving  stone. — Extracted  from  Gill's  Description.  See  Tech.  Repos.  for 
1828,  p.  219. 

The  late  Mr.  Henry  Guy's  method,  by  which  spheres  of  metal  and  other 
hard  substances,  are  produced  with  perfect  accuracy,  will  be  described  in 
Chap.  XXXIII.  Sect.  4,  of  this  volume. 

MARQUETRY  WORK.— This  term,  probably  derived  from  the  French  definitions, 
marqueterie  en  bris  and  marqueterie  en  metal,  (see  foot  note,  page  732,  vol.  2) 
has  been  selected  to  denote  a  variety  of  works,  also  known  as  buhl  work,  reisner 
work,  parquetage,  mosaic,  &c.,  in  which  two  or  more  woods,  metals,  and 
other  materials,  are  united  by  various  modes  of  inlaying,  some  of  which  are 
entirely  executed  with  the  saw,  as  described  in  pages  731  —  739.  The 
methods  of  polishing  these  works  depend  on  the  materials  of  which  they  are 
respectively  composed,  and  are  generally  as  follows. 

2. — MARQUETRY  ENTIRELY  OF  WOOD. — This  is  reduced  to  a  level  surface  with  the 
toothing  plane,  and  is  then  scraped  with  the  joiner's  scraper,  which  so  far  as 
possible  is  applied  obliquely  to  the  joints  of  the  marquetry,  as  when  the 
scraper  is  applied  parallel  with  the  joints,  or  broadside,  it  is  liable  to  dig 
down,  and  if  applied  at  right  angles  to  the  joints  it  does  not  cut  so  cleanly  as 
in  the  inclined  position,  like  the  skew  irons  of  some  rebate  planes.  The 
scraper  is  sometimes  employed  with  such  good  effect,  that  the  work  only 
requires  to  be  rubbed  with  a  few  of  its  own  shavings,  as  in  many  draftboards 
made  of  holly  and  ebony. 

When  the  scraper  is  less  successfully  used,  fine  glass  paper  on  a  flat  piece 
of  cork  is  employed  to  smooth  the  work,  and  the  paper  is  preferable,  if  it  is 
worn  until  it  almost  ceases  to  cut,  and  has  become  uniformly  choked  or 
clogged  with  the  fine  dust  from  the  work,  but  which  must  not  be  allowed  to 
collect  in  hard  partial  lumps,  a  condition  that  may  readily  occur  with  resinous 
or  greasy  woods,  as  these  lumps  would  scratch  the  work. 

3. — MARQUETRY  IN  WOOD  AND  METAL,  and  also  those  which  contain  ivory,  pearl  shell, 
tortoiseshell,  and  metals,  require  to  be  levelled  very  carefully  with  flat  files 
handled  after  the  manner  of  figs.  8 1 6  to  8 1 8,  page  834,  vol.  2,  ending  with  a  very 
smooth  flat  file,  after  which  the  scraper  should  be  used  if  practicable,  and 
followed  by  glass  or  emery  paper  employed  very  sparingly  as  above  directed. 
When  the  metal  preponderates  emery  paper  is  much  to  be  preferred,  and 
really  good  sand  paper,  which  is  of  an  intermediate  character  between  glass 
and  emery  paper,  has  also  been  used,  but  as  stated  above,  the  paper  of  which 
kind  soever,  should  have  but  very  little  cut,  should  be  applied  dry,  and 
allowed  to  become  clogged,  so  as  to  act  principally  as  a  hard  dry  rubber  or 
burnisher.  If  the  polishing  is  at  all  in  excess,  the  wood  will  inevitably  be 


AND    PROCESSES    FOR    GRINDING    AND    POLISHING.  1080 

worn  down  so  as  to  allow  the  metal  or  harder  material  to  project  above  the 
general  surface. 

It  is  always  particularly  hazardous  to  resort  to  wet  polishing  with  inlaid 
works,  as  if  the  water  is  carelessly  used,  there  is  risk  of  its  penetrating  to  the 
glue  and  loosening  the  pieces,  'and  if  the  woods  are  only  superficially 
wetted  they  are  apt  to  curl  up  at  the  edges  and  become  warped  ;  and 
besides  the  grain  of  the  wood  is  almost  certain  to  rise  with  the  wet  and  leave 
a  rough  unsightly  surface.  Oil  is  preferable  only  so  far  as  not  dissolving  the 
glue,  but  oil  or  water  are  alike  inapplicable  to  light- coloured  woods,  which 
are  almost  sure  to  become  stained  by  the  polishing  powders,  and  the  fluids 
used  in  their  lubrication. 

4. — MARQUETRY  ENTIRELY  OP  METAL,  which  is  less  common  and  more  recent  than 
the  foregoing  kinds,  is  first  smoothed  with  a  flat  file,  secondly  it  is  very  care 
fully  scraped  with  a  triangular  or  other  scraper,  thirdly  it  is  rubbed  with  a 
stick  of  snakestone  and  water,  fourthly  with  charcoal  in  the  stick  and  oil,  and 
it  is  finished  with  a  coil  of  list  or  other  rubber  supplied  with  rotteustoue 
and  oil. 

5. — MARQUETRY  WITH  VARNISHED  SURFACES. — Many  of  the  modern  marquetry 
works,  instead  of  having  their  surfaces  polished  simply  by  attrition  as  above 
described,  are  covered  with  varnish  either  applied  with  friction  as  in  the  so- 
called  French  polish,  or  the  varnish  is  laid  on  in  several  coats  with  a  brush 
and  polished  off  with  pumice-stone  and  rottenstone.  Previously  to  their 
being  varnished,  which  processes  will  be  hereafter  described,  the  marquetry 
works  are  levelled  with  the  file  or  scraper  as  the  case  may  be,  and  smoothed 
with  glass  paper. 

MEERSCHAUM  is  scraped  to  a  smooth  surface,  but  it  is  so  soft  as  scarcely  to 
admit  of  being  polished,  otherwise  than  by  dipping  the  meerschaum  into 
melted  wax  to  fill  up  its  pores,  and  rubbing  it  when  dry  with  a  flannel  ;  and 
which  is  the  usual  process. 
MILK  MEERSCHAUM  obtains  a  somewhat  different  treatment. 

MILL  a  general  termed  used  by  lapidaries  to  represent  their  different  wheels  ; 
as  roughing-mill,  cloth-mill,  etc.  See  the  introductory  article  on  WHEELS, 
also  Chap.  XXXIV.  on  LAPIDARY  WORK. 

MOSLINGS. — The  thin  shreds  or  shavings  of  leather  shaved  off  by  the  currier 
in  dressing  cow,  or  calf  skins.  They  are  frequently  used  for  removing  oil 
from  metals  that  are  being  polished  and  serve  extremely  well,  being  as  bibu- 
lous as  blotting  paper.  Cotton  waste  is  similarly  employed  especially  in  the 
vicinity  of  cotton  mills. 

MOTHER  OF  PEARL.— See  SHELLS. 
NACREOUS  SHELLS.— Idem. 


1081          DESCRIPTIVE    CATALOGUE    OF    APPARATUS,    MATERIALS, 
NORWAY  RAGSTONE.     See  HONE  SLATES,  article  1. 


OILSTONE. — The  Turkey  Oilstone  can  hardly  be  considered  as  a  hone  slate, 
having  nothing  of  a  lamellar  or  schistose  appearance.  As  a  whetstone,  it 
surpasses  every  other  known  substance,  and  possesses,  in  an  eminent  degree, 
the  property  of  abrading  the  hardest  steel,  and  is  at  the  same  time  of  so 
compact  and  close  a  nature,  as  to  resist  the  pressure  necessary  for  sharpen- 
ing a  graver,  or  other  small  instrument  of  that  description.  Little  more  is 
known  of  its  natural  history  than  that  it  is  found  in  the  interior  of  Asia 
Minor,  and  brought  down  to  Smyrna  for  sale.  The  white  and  black  varieties 
of  Turkey  oilstone,  differ  but  little  in  their  general  characters,  the  black  is, 
however,  somewhat  harder,  and  is  imported  in  larger  pieces  than  the  white. 

2. — OILSTONES  FITTED  IN  CASES. — The  rough  irregular  pieces  of  oilstone  scarcely 
ever  exceed  about  3  inches  square  and  10  inches  long,  and  are  generally 
about  one  third  smaller  ;  when  cut  into  rectangular  forms  it  is  done  with 
the  lapidary's  slitting  mill  and  diamond  powder,  the  blocks  are  then  rubbed 
smooth  with  sand  or  emery  on  an  iron  plate.  The  piece  of  oilstone  is 
generally  inlaid  in  a  block  of  wood,  in  which  it  is  cemented  with  the  putty 
used  by  glaziers,  and  to  avoid  the  deposition  of  dust  a  wooden  lid  is  usually 
added  ;  the  lid  is  sometimes  covered  with  a  thick  piece  of  buff  leather  which 
serves  to  absorb  the  oil  from  the  tool  and  is  used  in  the  manner  of  a  razor 
strop.  The  oil  employed  on  the  oilstone  should  be  indisposed  to  dry  or 
thicken,  in  this  respect  sperm  oil  is  the  best,  but  neats-foot  oil  is  nearly  as 
good,  and  has  no  offensive  smell. 

The  joiner  often  puts  three  or  more  small  points  in  the  stock  or  bed  of 
the  stone,  that  it  may  take  a  firm  hold  of  the  work  bench  when  dabbed  down 
thereupon  ;  and  the  turner  adds  two  fillets  so  that  it  may  fit  transversely  on 
the  bearers  of  the  lathe. 

3. — OILSTONE  SLIPS,  are  small  pieces  of  this  useful  stone  cut  into  different  forms  by 
the  lapidary.  Some  oilstone  slips  are  wide  thin  pieces,  the  edges  of  which 
are  rounded  to  adapt  them  to  the  curvatures  of  gouges,  and  such  slips  are 
usually  cut  wedge  form,  that  the  semicircular  edges  on  the  one  slip  may  be 
of  two  sizes  and  curvatures  ;  these  are  used  for  gouges,  for  various  figured 
tools  used  by  turners,  and  also  for  plane  irons  for  mouldings.  Other  Oil- 
stone slips  for  polishing  are  cut  into  pieces  from  \  to  -|  inches  square  and 
3  to  6  inches  long,  to  be  used  after  the  manner  of  files,  by  mechanicians, 
watchmakers  and  other  artizans. 

4. — OILSTONE  POWDER. — Fragments  of  oilstone  when  pulverised  sifted  and  washed, 
are  much  in  request  by  mechanicians.  This  abrasive  is  generally  preferred 
for  grinding  together  those  fittings  of  mathematical  instruments  and 
machinery,  which  are  made  wholly  or  in  part  of  brass  or  gun  metal  ;  for 
oilstone  being  softer  and  more  pulverulent  than  emery,  is  less  liable  to 
become  embedded  in  the  metal  than  emery,  which  latter  is  then  apt  conti- 
nually to  grind,  and  ultimately  damage  the  accuracy  of  the  fittings  of  brass 
works.  In  modern  practice  it  is  usual,  however,  as  far  as  possible  to  discard 


AND    PROCESSES    FOR    GRINDING    AND    POLISHING.  1082 

the  grinding  together  of  surfaces,  with  the  view  of  producing  accuracy  of 
form  or  precision  of  contact. 

Oilstone  powder  is  preferred  to  pumice-stone  powder  for  polishing  supe- 
rior brass  works,  and  it  is  also  used  by  the  watchmaker  on  rubbers  of 
pewter  in  polishing  steel. 

ONYX,  a  variety  of  Chalcedony  that  is  wrought  by  the  lapidary  like  Carnelian. 

OPAL. — This  beautiful  iridescent  gem,  although  soft  is  very  brittle  and  tender, 
on  account  of  the  numerous  fissures  by  which  it  is  traversed,  and  that 
apparently  give  rise  to  the  splendid  play  of  colours  seen  in  precious  opals  of 
fine  quality.  Opals  are  always  cut  with  rounded  faces,  and  are  more 
generally  treated  like  alabaster  than  carnelian. 

OXIDES  OF  IRON. — The  red  and  black  oxides  of  iron,  and  mixtures  of  them, 
are  prepared  by  manufacturing  chemists  at  Liverpool,  Sheffield,  Derby  and 
elsewhere,  as  polishing  powders,  commercially  known  as  crocus,  rouge,  red 
stuff,  colcothar  of  vitriol,  &c.,  and  the  same  substances  are  also  employed  as 
pigments,  under  the  names  of  red-brown,  purple-brown,  &c.  The  ordinary 
manufacture  of  crocus  will  be  first  noticed,  and  then  the  more  exact  method, 
required  in  the  higher  branches  of  scientific  art,  in  order  completely  to  avoid 
the  accidental  admixtures  of  silex  and  other  impurities.  As  however  these 
several  matters  have  been  elsewhere  described  with  great  exactness,  it  is 
conceived  best  to  quote  these  passages,  and  it  is  to  be  observed  that  articles 
1,  4,  6  and  7  are  literal  extracts  from  Mr.  Thomas  Gill's  paper  on  the  pre- 
paration of  the  metallic  oxides,  contained  in  Tech.  Repos.  vol.  1,  pages  431-5. 

1. — CROCUS  AND  ROUGE. — "  These  articles  are  manufactured  at  Liverpool,"  said  the 
late  Mr.  Samuel  Varley,  "  by  persons  who  make  it  their  sole  occupation, 
in  the  following  manner.  They  take  crystals  of  sulphate  of  iron,  (green 
vitriol  or  copperas,)  immediately  from  the  crystallising  vessels,  hi  the 
copperas  works  there,  so  as  to  have  them  as  clean  as  possible  ;  and  in- 
stantly put  them  into  crucibles  or  cast  iron  pots,  and  expose  them  to 
heat,  without  suffering  the  smallest  particles  of  dust  to  get  in,  which  would 
have  a  tendency  to  scratch  the  articles  to  be  polished.  Those  portions  which 
are  least  calcined,  and  are  of  a  scarlet  colour,  are  fit  to  make  rouge  for 
polishing  gold  or  silver  ;  whilst  those  which  are  more  calcined,  or  have  become 
red,  purple,  or  bluish  purple,  form  crocus  fit  for  polishing  brass  or  steel.  Of 
these,  the  bluish-purpled  coloured  part  are  the  hardest,  and  are  found  nearest 
to  the  bottom  of  the  vessels,  and  consequently  have  been  exposed  to  the 
greatest  degree  of  heat." 

2. — MR.  ANDREW  Ross's  MODE  OF  PREPARING  OXIDES  OF  IRON. — "Dissolve 
crystals  of  sulpKate  of  iron  in  water  ;  filter  the  solution,  to  separate  some 
particles  of  silex  which  are  generally  present  and  sometimes  are  abundant ; 
then  precipitate  from  this  filtered  solution  the  protoxide  of  iron  by  the  addi- 
tion of  a  saturated  solution  of  soda,  which  must  also  be  filtered.  This  gray 


1083        DESCRIPTIVE    CATALOGUE    OF    APPARATUS,    MATERIALS, 

oxide  is  to  be  repeatedly  washed  and  then  dried  ;  put  it  in  this  state  into  a 
crucible,  and  very  gradually  raise  it  to  a  dull  red  heat ;  then  pour  it  into  a 
clean  metal  or  earthen  dish,  and  while  cooling  it  will  absorb  oxygen  from  the 
atmosphere,  and  acquire  a  beautiful  dark-red  colour.  In  this  state  it  is  fit 
for  polishing  the  softer  metals,  as  silver  and  gold,  but  will  scarcely  make  any 
impression  on  hardened  steel  or  glass.  For  these  latter  purposes,  I  dis- 
covered that  it  is  the  black  oxide  that  effected  the  polish,  (and  this  gives  to 
the  red  oxide  a  purple  hue,  which  is  used  as  the  criterion  of  its  cutting  quality 
in  ordinary,)  therefore,  for  polishing  the  harder  materials,  the  oxide  must  be 
heated  to  a  bright  red,  and  kept  in  that  state  until  a  sufficient  quantity  of 
it  is  converted  into  black  oxide  to  give  the  mass  a  deep  purple  hue  when 
exposed  to  the  atmosphere.  I  have  converted  the  whole  into  black  oxide  ; 
but  this  is  liable  to  scratch,  and  does  not  work  so  pleasantly  as  when  mixed 
with  the  softer  material.  The  powder  must  now  be  levigated  with  a  soft 
wrought  iron  spatula,  upon  a  soft  iron  slab,  and  afterwards  washed  in  a  very 
weak  solution  of  gum-arabic  as  recommended  by  Dr.  Green  in  his  paper  on 
Specula.  The  oxide  prepared  in  this  manner  is  almost  impalpable,  and  free 
from  all  extraneous  matter,  and  has  the  requisite  quality  in  an  eminent 
degree  for  polishing  steel,  glass,  the  softer  gems,  &c.  See  EMERY,  article  4. 

3. — LORD  ROSSE'S  MODE  OF  PREPARING  THE  PEROXIDE  OF  IRON. — "I  prepare  the 
peroxide  of  iron  by  precipitation  with  water  of  ammonia  from  a  pure  dilute 
solution  of  sulphate  of  iron  ;  the  precipitate  is  washed,  pressed  in  a  screw  press 
till  nearly  dry,  and  exposed  to  a  heat  which  in]the  dark  appears  a  dull  low  red. 
The  only  points  of  importance  are,  that  the  sulphate  of  iron  should  be  pure, 
that  the  water  of  ammonia  should  be  decidedly  in  excess,  and  that  the  heat 
should  not  exceed  that  I  have  described.  The  colour  will  be  a  bright  crimson 
inclining  to  yellow.  I  have  tried  both  potash  and  soda  pure  instead  of  water  of 
ammonia,  but  after  washing  with  some  degree  of  care,  a  trace  of  the  alkali 
still  remained,  and  the  peroxide  was  of  an  ochrey  colour  till  overheated,  and 
did  not  polish  properly."  See  Phil.  Trans.,  1840,  p.  521. 

4. — JEWELLERS'  ROUGE "  Is  prepared  by  persons  in  this  metropolis,  by  decom- 
posing sulphate  of  iron  with  potash  ;  well  washing  the  yellow  oxide  of  iron, 
to  free  it  from  the  sulphate  of  potash  ;  and  slightly  calcining  it,  till  it  acquires 
a  scarlet  colour." 

5. — SPECULAR  IRON  ORE  when  finely  pulverized  and  washed,  makes  a  polishing 
powder  which  is  greatly  recommended  by  Mr.  Heath  for  razor  strops  and 
other  uses.  It  closely  resembles  both  in  appearance  and  effect  the  crocus 
artificially  prepared  from  the  sulphate  of  iron. 

6. — ARTIFICIAL  SPECULAR  IRON  ORE. — "  This  is  made  in  the  following  manner. 
Equal  parts  of  sulphate  of  iron  and  hydrochlorate  of  soda,  (common  salt,)  are 
to  be  well  mixed,  by  rubbing  them  together  in  a  mortar :  the  mixture  is  then 
to  be  put  into  a  shallow  cupel  or  crucible,  and  exposed  to  a  red-heat :  a  con- 
siderable quantity  of  vapour  will  be  disengaged,  and  the  matter  will  run  into 
fusion.  When  vapours  no  longer  arise,  remove  the  vessel,  and  let  it  cool. 
"  The  mass  will  be  of  a  violet-brown  colour,  covered  with  extremely  brilliant 


AND     PROCESSES    FOR    GRINDING    AND    POLISHING.  1084 

scales  resembling  mica,  and  perfectly  like  the  specular  iron-ore.  This  mass 
must  be  dissolved  in  water  ;  as  well  to  separate  the  sulphate  of  soda  which 
is  formed  by  the  decomposition  of  the  two  salts  employed,  as  to  wash  over 
the  lighter  particles  of  uncrystallized  oxide,  which  forms  an  excellent 
polishing  powder. 

"  The  fire  must  not  be  continued  too  long,  nor  be  too  violent ;  for  then  the 
powder  would  become  black,  extremely  hard,  and  produce  no  good  effect. 
The  artificial  specular  iron  ore  is  the  more  preferred,  the  nearer  it  approxi- 
mates to  the  violet  colour. 

"  The  micaceous  scales  which  subside  after  the  washing  over  of  the  powdery 
part,  afford  an  excellent  material  for  razor  strops,  when  applied  to  the  strop 
with  a  little  grease  previously  rubbed  over  it  j  as  we  can  vouch,  from  our 
own  experience  in  the  use  of  it,  for  several  months  past." 

It  has  been  suggested  to  the  author  by  an  experienced  chemist,  that  the 
atomic  proportions  of  the  sulphate  of  iron  and  common  salt,  should  be  taken 
for  the  last  process,  and  when  it  is  considered  that,  as  noticed  by  the  Earl  of 
Rosse,  the  present  limit  of  perfection  hi  the  polishing  of  specula,  depends 
mainly  on  the  fineness  and  efficiency  of  the  polishing  material,  it  becomes 
evident  that  the  subject  demands  every  care  hi  its  investigation,  and  which 
may  apologize  for  the  length  of  the  foregoing  articles. 

7. — AN  IMPROVED  TRIPOLI,  FOR  POLISHING  GOLD  AND  SILVER. — "  The  basis  of  this 
excellent  Tripoli  consists  of  a  mineral  substance,  abundantly  found  in  the 
coal  and  iron  mines  of  Staffordshire,  &c.  &c. ;  known  by  the  name  of  dunch, 
or  curl  stone.  It  had  formerly  been  employed  for  no  other  purpose  than  as 
a  material  for  mending  the  roads.  It  is  a  compound  of  iron,  alumine,  lime, 
and  silex." — Mr.  Gill  proposed  this  application  of  clunck  from  the  external 
and  chemical  resemblance  it  bears  to  Septaria — the  well-known  basis  of  the 
Roman  Cement,  the  employment  of  which  in  polishing  he  had  previously 
advocated  in  the  Annals  of  Philosophy.  He  goes  on  to  say — "The  polishing 
effects  of  the  calcined  and  pulverized  duncli  are  however  still  superior  to 
that  of  the  Septaria,  when  prepared  in  a  similar  manner  ;  and  are,  indeed, 
in  point  of  quickness  of  action  in  producing  the  polish,  and  in  the  beautiful 
black  lustre  which  it  gives  to  the  gold  or  silver,  far  beyond  any  thing  I  have 
ever  met  with." 

OXIDES  OF  LEAD  AND  TIN.— See  PUTTY  POWDER. 

PAINTED  WORKS,  such  as  the  panels  of  carriages,are  first  grounded,  or  carefully 
painted  three  or  four  times  in  good  oil  colour,  and  when  thoroughly  dry  and 
hard,  the  surface  of  the  paint  is  rubbed  smooth  with  a  lump  of  pumice-stone 
plentifully  supplied  with  water  ;  two  pieces  of  pumice-stone  are  used  and 
continually  rubbed  together  to  remove  the  paint  accumulated  on  their  sur- 
faces. The  finishing  colour,  which  is  frequently  ground  up  in  varnish, 
instead  of  oil,  is  then  laid  on,  and  the  panels  after  having  had  three  or  four 
coats  of  carriage  varnish,  (a  description  of  copal  varnish,)  are  carefully 
polished  first  with  a  rag  supplied  with  pulverized  pumice-stone  and  water, 


1085          DESCRIPTIVE    CATALOGUE    OF    APPARATUS,    MATERIALS, 

and  then  with  rottenstone  and  oil  on  other  rubbers  :  the  worsted  stocking 
being  here  likewise  in  great  requisition  for  the  purpose. 

PALLADIUM. — Palladium,  platinum  and  silver  when  inlaid  in  the  limbs  of  mathe- 
matical instruments,  are  treated  much  the  same  as  platinum,  which  see. 

PASTES,  or  factitious  gems  made  in  coloured  glass,  are  polished  after  the  mode 
employed  for  the  gems  themselves,  and  the  succession  of  the  mills  and  pow- 
ders used  by  the  lapidary  for  the  purpose  is  nearly  the  same  as  that  described 
under  CARNELIAN.  Facets  on  pastes,  are  cut  on  a  lead  mill  with  flour  emery, 
and  polished  on  pewter  with  rottenstone,  but  the  particulars  of  this  part  of 
the  lapidaries'  art  will  be  found  in  Chap.  XXXIV.  The  description  of  the 
principal  Factitious  Diamonds  will  be  found  under  DIAMOND,  article  5. 

PEARL  SHELL,  or  Mother  of  Pearl. — See  SHELLS. 

PEBBLES. — Although  these  differ  much  in  their  colour  and  general  appearance, 
they  may  be  viewed  as  varieties  of  Agate,  and  are  treated  as  such,  or  in  the 
mode  fully  described  under  the  head  CARNELIAN. 

PERIDOT.— See  CHRYSOLITE. 

PEWTER  is  seldom  polished  ;  the  articles  when  left  from  the  turning  tool  or 
scraper,  are  burnished  with  plenty  of  oil,  the  oil  is  removed  with  a  rag  and 
whiting,  and  this  is  the  only  polish  given.  Pewter  vessels  are  mostly  cleaned 
with  silver  sand  and  water,  or  with  liquids  containing  potash  or  soda,  to 
remove  the  grease. 

PEWTER  is  much  used  for  laps  and  polishers  by  lapidaries,  jewellers,  watch- 
makers and  many  others.  The  metal  of  old  pewter  plates  is  preferred,  but 
tin  unalloyed  appears  to  be  nearly  identical  in  effect. 

PLASMA,  which  is  a  variety  of  Chalcedony,  is  polished  like  CARNELIAN. 

PLASTER  OF  PARIS. — In  removing  the  seams  left  from  the  mould  a  knife  or 
scraper  is  first  used  and  the  work  is  then  rubbed  with  Dutch  rush,  or  fish 
skin  previously  softened  in  water.  The  cleaning  off  is  best  done  before  the 
plaster  is  dry. 

PLASTER  OF  PARIS  is  made  very  closely  to  resemble  ivory,  by  the  following 
process,  invented  by  Mr.  Franchi,  an  Italian  figure  caster : — Plaster  and 
colouring  matter,  are  employed  in  the  proportions  of  one  pound  of  superfine 
plaster  of  Paris,  to  half  an  ounce  of  Italian  yellow  ochre  reduced  to  the  finest 
powder,  they  are  intimately  mixed  by  passing  them  together  through  a  fine 
sieve,  after  which  the  plaster  cast  is  made  in  the  usual  way.  It  is  first 
allowed  to  dry  in  the  open  air,  and  is  then  carefully  heated  in  an  oven,  (one 
that  is  used  for  culinary  purposes  will  answer,)  the  hot  plaster  cast  when 
thoroughly  dry,  is  soaked  for  one  quarter  of  an  hour  in  a  bath  containing 


AND    PROCESSES    FOR    GRINDING    AND    POLISHING.  1086 

equal  parts  of  white  wax,  spermaceti,  and  stearine,  heated  just  a  little  beyond 
the  melting  point.  The  cast  on  removal  is  set  on  edge  that  the  superfluous 
composition  may  drain  off,  and  before  it  cocls  its  surface  is  brushed  with  a 
brush  like  that  known  by  house  painters  as  a  sash  tool,  to  remove  any  wax 
which  may  have  settled  in  the  crevices,  and  finally  when  the  plaster  is  entirely 
cold,  its  surface  is  polished  by  rubbing  it  with  a  tuft  of  cotton  wool. 

Mr.  Franchi's  specimens,  some  of  which  are  very  classical  and  in  high 
relief,  are  cast  in  a  peculiar  manner  in  elastic  moulds  ;  and  although  he 
states  the  above  to  be  the  usual  proportions  of  the  yellow  ochre  for  a  medium 
tint,  the  quantity  may  be  reduced  or  increased  for  paler  or  darker  shades. 
He  adds  that  the  brown  discoloured  parts  in  old  carvings  in  ivory,  are  some- 
times imitated  in  water  colours  with  a  camel  hair  pencil  before  the  works 
are  dipped  in  the  composition,  which  entirely  defends  them  from  the  action 
of  the  air,  and  permits  them  to  be  washed  with  soap  and  water  if  so  required. 

Mr.  Franchi  was  rewarded  by  the  Society  of  Arts  for  this  invention 
in  1846. 

PLATE  GLASS.— The  polishing  of  this  beautiful  material  is  slightly  noticed  in 
Chap.  XXXIII.  Sect.  1. 

PLATINUM  is  very  difficult  to  file  and  polish,  but  these  processes  are  not  often 
required,  as  the  great  use  of  platinum  is  for  chemical  apparatus,  which  are 
wrought  almost  exclusively  with  the  hammer  and  soldered  with  pure  gold. 
Platinum  is  sometimes  inlaid  in  the  limbs  of  mathematical  instruments  to 
receive  the  graduations,  and  then  in  filing  this  peculiar  metal,  the  file  is 
generally  moistened  with  oil  to  prevent  it  from  tearing  up ;  and  in  polishing 
platinum  the  mathematical  instrument  makers  use  1st,  water  of  Ayr  stone  ; 
2ndly,  blue  stone  ;  3dly,  charcoal, — all  with  water  ;  and  4thly,  they  lay  the 
grain  with  charcoal  and  abundance  of  oil,  in  order  that  the  metallic  particles 
may  be  floated  away.  It  is  necessary  to  use  two  pieces  of  charcoal,  and 
these  are  rubbed  together  at  short  intervals,  in  order  to  remove  from  the 
one,  those  minute  particles  of  metal  which  become  embedded  in  the  other, 
and  that  if  allowed  to  remain  would  scratch  the  work. 

POLISHING  SLATES.—  See  HONE  SLATES,  articles  8,  9,  and  15. 
PORCELLANOUS  SHELLS.— See  SHELLS. 

PORPHYRY  is  not  much  used  in  this  country,  but  is  successfully  worked  in 
Sweden, — first  with  the  pick  and  chisels,  and  afterwards  by  grinding  it  into 
form  with  emery  and  water  applied  through  the  medium  of  heavy  rubbers, 
also  of  porphyry.  As  in  other  cases  it  is  needful  to  employ  a  gradual  suc- 
cession of  emery  as  to  coarseness,  It  is  probable  the  final  polish  is  obtained 
by  rubbers  of  wood  with  flour  emery,  and  wood  covered  with  buff  or  felt 
and  fed  with  crocus,  much  the  same  as  in  the  treatment  known  to  be  applied 


1087        DESCRIPTIVE    CATALOGUE    OF    APPARATUS,    MATERIALS, 

to  granite.  From  the  homogeneity  of  porphyry  it  is  less  difficult  to  manage 
than  granite,  but  they  each  demand  great  time  and  patience. 

The  Elvans  of  Cornwall  require  similar  treatment  to  porphyry  and  granite, 
between  which  they  are  systematically  placed. 

By  the  lapidary  porphyry  is  treated  like  AGATE  or  CARNELIAN. 

POTSTONE,  a  magnesian  mineral,  allied  to  Serpentine  and  Steatite,  is  very  soft 
when  first  raised,  and  then  admits  of  being  very  easily  turned  with  chisels  of 
various  forms.  See  vol.  1,  page  166.  The  common  practice  in  Germany 
for  polishing  the  Potstone,  is  to  use  first  sand  and  water,  and  afterwards 
tripoli  and  water,  occasionally  also  rottenstone  and  oil  for  the  highest  gloss, 
the  whole  are  mostly  applied  on  woollen  cloths. 

When  the  lapidary  polishes  the  Potstone,  is  it  usually  by  the  process 
recommended  for  Alabaster,  unless  from  long  exposure  it  has  become  har- 
dened, and  then  it  is  worked  as  Carnelian. 

"  PUMICE-STONE  is  a  volcanic  product,  and  is  obtained  principally  from  the 
Campo  Bianco,  one  of  the  Lipari  islands,  which  is  entirely  composed  of 
this  substance.  It  is  extensively  employed  in  various  branches  of  the  arts, 
and  particularly  in  the  state  of  powder,  for  polishing  the  various  articles  of 
cut  glass ;  it  is  also  extensively  used  in  dressing  leather,  and  in  grinding 
and  polishing  the  surface  of  metallic  plates,  &c." 

Pumice-stone  is  ground  or  crushed  under  a  runner,  and  sifted,  and  in  this 
state  it  is  used  for  brass  and  other  metal  works,  and  also  for  japanned,  var- 
nished, and  painted  goods,  for  which  latter  purposes  it  is  generally  applied  on 
woollen  cloths  with  water. 

PUTTY  POWDER  is  the  pulverised  oxide  of  tin,  or  generally  of  tin  and  lead 
mixed  hi  various  proportions, — the  process  of  manufacture  is  alike  in  all 
cases.  The  metal  is  oxidized  in  an  iron  muffle,  or  a  rectangular  box,  close 
on  all  sides,  except  a  square  hole  in  the  front  side.  The  retort  is  surrounded 
by  fire  and  kept  at  the  red  heat,  so  that  its  contents  are  partially  ignited, 
and  they  are  continually  stirred  to  expose  fresh  portions  to  the  heated  air  ; 
the  process  is  complete  when  the  fluid  metal  entirely  disappears,  and  the 
upper  part  of  the  oxide  then  produced,  sparkles  somewhat  like  particles  of 
incandescent  charcoal.  The  oxide  is  then  removed  with  ladles  and  spread 
over  the  bottom  of  large  iron  cooling  pans  and  allowed  to  cool.  The  lumps 
of  oxide,  which  are  as  hard  as  marble,  are  then  selected  from  the  mass  and 
ground  dry  under  the  runner,  the  putty  powder  is  afterwards  carefully 
sifted  through  lawn. 

As  a  criterion  of  quality  it  may  be  said  that  the  whitest  putty  powder 
is  the  purest  provided  it  be  heavy,  some  of  the  common  kinds  are  brown 
and  yellow,  whilst  others  from  the  intentional  admixture  of  a  little  ivory 
black  are  known  as  grey  putty.  The  pure  white  putty,  and  which  is  used 
by  marble  workers,  opticians,  and  some  others,  is  the  smoothest  and  most 
cutting  ;  it  should  consist  of  the  oxide  of  tin  alone,  but  to  lessen  the 


AND    PROCESSES    FOR    GRINDING    AND     POLISHING.  1088 

difficulty  of  manufacture,  a  very  little  lead,  (the  linings  of  tea  chests,)  or 
else  an  alloy  called  shruff  (prepared  in  ingots  by  the  pewterers)  is  added  to 
assist  the  oxidation. 

The  putty  powder  of  commerce  of  good  fair  quality,  is  made  of  about 
equal  parts  of  tin  and  lead,  or  tin  and  shruff ;  the  common  dark  coloured 
kinds  are  prepared  of  lead  only,  but  these  are  much  harsher  to  the  touch 
and  altogether  inferior. 

Perhaps  the  most  extensive  use  of  putty  powder  is  in  glass  and  marble 
works,  but  the  best  kind  serves  admirably  as  plate  powder,  and  for  the 
general  purposes  of  polishing. 

2. — PUTTY  POWDER  FOR  FINE  OPTICAL  PURPOSES  is  prepared  by  Mr.  A.  Ross  by 
the  following  method,  which  is  the  result  of  many  experiments.  Metallic 
tin  is  dissolved  in  nitro-muriatic  acid,  and  precipitated  from  the  filtered 
solution  by  liquid  ammonia,  both  fluids  being  largely  diluted  with  water. 
The  per-oxide  of  tin  is  then  washed  in  abundance  of  water,  collected  on  a 
cloth  filter,  and  sqvieezed  as  dry  as  possible  in  a  piece  of  new  clean  linen  ; 
the  mass  is  now  subjected  to  pressure  in  a  screw  press,  or  between  lever 
boards,  to  make  it  as  dry  as  possible.  When  the  lump  thus  produced  has 
been  broken  in  pieces  and  dried  in  the  air,  it  is  finely  levigated  while  dry, 
on  a  plate  of  glass  with  an  iron  spatula,  and  afterwards  exposed  in  a  crucible 
to  a  low  white  heat. 

Before  the  per-oxide  has  been  heated,  or  whilst  it  is  in  the  levigated 
hydrous  state,  the  putty  powder  possesses  but  little  cutting  quality,  as  under 
the  microscope  the  particles  then  appear  to  have  no  determined  form,  or  to 
be  amorphous,  and  on  being  wetted  to  resume  the  gelatinous  condition  of  the 
hydrous  precipitate,  so  as  to  be  useless  for  polishing  ;  whereas  when  the 
powder  is  heated,  to  render  it  anhydrous,  most  of  the  particles  take  their 
natural  form,  that  of  lamellar  crystals,  and  act  with  far  more  energy,  (yet 
without  scratching,)  than  any  of  the  ordinary  polishing  powders.  The  whole 
mass  requires  to  be  washed  or  elutriated  in  the  usual  manner  after  having 
been  heated,  in  order  to  separate  the  coarser  particles. 

Mr.  Ross  usually  adds  a  little  crocus  to  the  putty  powder  by  way  of  colour- 
ing matter,  as  it  is  then  easier  to  learn  the  quantity  of  powder  that  remains 
on  the  polishing  tool ;  and  it  may  be  added  that  this  is  the  polishing  powder 
employed  by  Mr.  Ross  in  making  his  recently  improved  achromatic  object 
glasses  for  astronomical  purposes. 

QUARTZ. — Pure  silex,  occurs  both  crystalline  and  amorphous  and  is  polished 
after  the  mode  described  for  CARNELIAN.  The  reader  is  also  referred  to  the 
article  CRYSTAL,  by  which  name  Quartz  is  very  commonly  known  in  the  arts. 


LGSTONE.— See  HONE  SLATES,  article  1 . 


RAGST 

RED  STUFF. — A  name  applied  by  watchmakers  to  some  kinds  of  crocus,  or  the 
oxide  of  iron,  the  manufacture  of  which  is  described  under  the  head  OXIDE 
OF  IRON. 


1089         DESCRIPTIVE    CATALOGUE    OF    APPABATUS,  MATERIALS, 

RHODIUM,  which  is  an  extremely  hard  metal,  is  generally  figured  and  ground  on 
an  iron  lap,  into  the  surface  of  which  fragments  of  diamond  have  been  ham- 
mered. As  a  temporary  expedient  rhodium  may  be  polished  on  a  brass  lap 
with  oilstone  powder  and  oil,  using  a  high  velocity. 

ROCK  CRYSTAL.— See  CRYSTAL. 

ROTTENSTONE  is  a  variety  of  Tripoli,  almost  peculiar  to  England,  and  proves  a 
most  valuable  material  for  giving  polish  and  lustre  to  a  great  variety  of 
articles,  as  silver,  the  metals,  glass,  and  in  the  hands  of  the  lapidary  even  to 
the  hardest  stones.  It  is  found  in  considerable  quantities  both  in  Derby- 
shire and  South  Wales. 

ROUGE. — See  J)XIDE  OF  IRON,  articles  1  and  4. 

RUBBERS. — The  rubbers  used  in  polishing  often  follow  very  nearly  the  form  of 
the  plane,  the  file,  or  the  turning  tool,  accordingly  as  the  respective  artizans 
use  the  plane,  file,  or  turning  tool  in  their  several  avocations.  For  instance, 
the  carpenter  wraps  glass  paper  around  a  square  flat  piece  of  cork  ;  the 
smith  and  others  using  files,  fold  emery  paper  upon  that  instrument,  or  use, 
after  the  manner  of  the  file,  square  pieces  of  wood  and  metal  fed  with  the 
several  powders  mixed  with  oil,  and  they  also  employ  either  the  sides  or  the 
sloping  ends  of  square  slips  of  the  polishing  stones. 

Many  of  the  turned  works  in  the  metals,  &c.  are  polished  with  pointed 
sticks  of  deal,  by  the  ends  of  which  the  gritty  substances  are  forcibly  applied 
as  the  work  revolves. 

2. — THE  RUBBER  USED  BY  MASONS  AND  STATUARIES  is  frequently  a  slab  of  grit 
stone,  to  which  a  handle  is  attached  by  means  of  an  iron  strap,  or  cement. 
Sometimes  the  handle  is  short  and  perpendicular,  at  other  times  long  and 
horizontal,  or  inclined  at  a  small  angle  or  loosely  attached  by  an  eye  bolt, 
and  stones  of  two  or  three  qualities,  from  coarse  to  fine,  are  used  in  succes- 
sion. The  same  forms  are  also  given  to  the  handles  of  flat  plates  of  iron  and 
lead  that  are  fed  with  sharp  sand  for  polishing  stone,  or  with  emery  for 
metal ;  and  the  plate  may  in  this  case  be  made  of  such  a  weight  as  to  supply 
the  required  pressure,  leaving  to  the  workman  alone  to  put  it  in  movement  to 
and  fro  upon  the  work,  with  strokes  evenly  distributed  throughout  its  svirface. 

3. — THE  BLOCK  OR  CLOTH  RUBBER  USED  FOR  MARBLE,  consists  of  a  wooden  block 
about  12  or  14  inches  long,  3  to  6  wide,  and  2  to  3  thick,  a  hole  is  bored  through 
the  wood  at  one  end  for  a  transverse  stick  or  handle  which  projects,  horizon  tally 
on  both  sides,  and  there  are  fillets  of  wood  on  the  top  by  which  lumps  of 
lead  are  temporarily  affixed  to  give  the  required  pressure.  Felted  cloth  nearly 
half  an  inch  thick,  (called  nap,}  is  fixed  below  the  rubber  by  folding  the 
cloth  a  little  way  up  the  ends  and  nailing  it,  or  thinner  woollen  and  also  one 
or  more  layers  of  coarse  linen  cloth  are  also  used  according  to  the  degree  of 
hardness  required. 

4. — LARGE  CLOTH  RUBBERS  for  polishing  marble  are  sometimes  made  of  woollen 


AND    PROCESSES    FOR    GRINDING    AND    POLISHING.  1090 

or  other  rags  placed  in  a  rectangular  iron  frame,  connected  by  two  side  screws 
which  compress  the  rags  into  a  dense  mass,  the  surface  of  which  is  allowed 
to  wear  itself  flat  or  it  is  levelled  with  a  red-hot  iron  ;  sometimes  the  ring  is 
entire  and  the  rags  are  fixed  by  wedges,  at  other  times  the  ring  is  in  two 
parts  and  connected  by  side  screws  to  produce  the  compression,  and  a  socket 
is  added  for  the  attachment  of  the  handle  by  which  the  rubber  is  moved. 

5. — SMALL  CLOTH  RUBBERS  OR  ROLLERS,  used  for  various  purposes  in  polishing,  are 
commonly  made  of  a  coil  of  list  or  the  selvedge  of  woollen  cloth,  wound  up 
spirally  to  the  diameter  of  two  to  four  inches  and  tied  round  tightly  with 
string.  They  are  usually  covered  with  a  cloth  of  some  kind  that  may  easily 
be  renewed. 

6. — RUBBERS  FOR  FRENCH  POLISHING  are  made  of  little  balls  of  wadding,  (that  used 
for  ladies  dresses,)  covered  with  a  linen  rag.  The  rubber  is  placed  on  the 
open  mouth  of  the  bottle  which  is  then  turned  up,  the  varnish  thus  collected 
is  covered  with  a  second  rag,  and  moistened  with  one  or  two  drops  of  linseed 
oil,  the  varnish  gradually  exudes  according  to  the  degree  of  pressure  given 
to  the  ball,  which  is  of  about  the  size  of  a  walnut,  and  is  thrown  away  after 
four  or  five  minutes'  use,  as  it  hardens  from  the  accumulation  of  the  varnish 
and  then  scratches  instead  of  polishing  the  work. 

RUBY. — See  SAPPHIRE,  of  which  it  is  considered  to  be  a  variety.  For  the  preparation 
of  ruby  holes  for  the  pivots  of  watches,  see  vol.  1,  pages  178 — 9. 

RUMBLE  or  Shaking  Machine. — This  is  a  contrivance  sometimes  used  for  polishing 
small  articles  principally  by  their  attrition  against  each  other.  The  rumble 
is  a  cylindrical  vessel  with  a  side  door  for  the  introduction  of  the  work,  and 
is  generally  made  to  revolve  as  a  churn  by  a  winch  handle  or  pulley,  or  is 
shaken  endways  by  a  crank  in  imitation  of  the  mode  of  cleaning  nails  in  a 
sack,  and  it  is  thence  called  a  shaking  machine.  The  following  are  some  of 
the  uses  of  the  rumble  in  mechanical  works  : — 

For  scouring  small  castings  to  remove  the  sand  coat. 

For  brightening  iron  tacks  previously  to  their  being  tinned,  water  is  in 
this  case  introduced. 

For  polishing  steel  pens  with  sawdust  after  they  are  hardened  and 
tempered. 

For  polishing  needles  and  brass  pins  with  saw  dust  or  bran. 

For  polishing  bone  buttons  with  Trent  sand. 

For  polishing  lead  shot  with  black-lead  powder. 

For  cleaning  the  rust  from  cannon  balls  by  their  attrition  against  each 
other. 

For  drying  small  articles  in  saw  dust  after  they  have  been  annealed  and 
pickled  with  acid,  as  in  the  blanks  for  coin. 

For  dissolving  gums  in  spirits  of  wine  as  in  making  lackers  and  varnishes 
— and  to  which  processes  might  be  added  numerous  others. 

SAND,  which  is  nearly  pure  silex,  is  used  in  sawing  and  smoothing  building  stones 

VOL.    III.  F 


J091  DESCRIPTIVE    CATALOGUE    OF    APPARATUS,    MATERIALS, 

and  marbles,  and  in  many  other  of  the  preliminary  grinding  and  polishing 
processes.  River  sand  and  pit  sand  are  in  general  sharper  than  sea  sand, 
which  is  more  rounded  by  attrition.  Stone  masons  prefer  the  scrapings  of 
roads  that  have  been  repaired  with  flint  stones,  the  particles  of  which 
become  knocked  off  and  abraded  by  the  traffic  ;  and  engineers  sometimes 
employ  grindstone  dust,  collected  after  turning  the  grindstone  into  form,  or 
obtained  by  crushing  the  grit  or  sandstone  with  a  hammer:  or  pestle  and 
mortar,  as  the  grindstone  dust  cuts  more  sharply  than  Flanders  brick, 
another  form  in  which  sand  is  employed. 

2. — TRENT  SAND  is  collected  from  the  banks  of  the  river  of  that  name  which  runs 
into  the  Humber.  It  is  largely  employed  at  Sheffield,  and  somewhat  throughout 
England  generally,  for  polishing.  This  sand  is  remarkably  fine  and  sharp, 
and  serves  very  economically  many  of  the  purposes  of  emery  and  other 
polishing  powders  prepared  by  art,  it  is  very  much  used  for  Britannia 
metal  goods. 

The  Sheffield  cutlers  are  in  the  habit  of  making  the  Trent  sand  with  water, 
into  balls  two  or  three  inches  diameter.  The  balls  when  dry  are  burned  for 
a  few  hours  in  the  kitchen  fire,  and  from  being  of  a  moderately  dark  brown, 
become  brick  red.  The  lumps  are  then  crushed  between  the  hands  and 
passed  through  a  fine  hair  sieve.  The  burnt  sand  is  considered  to  cut 
quicker  than  the  unburnt. 

For  common  work  they  use  the  blue  stone  pulverized  and  sifted  instead  of 
Trent  sand,  that  is,  the  blue  grit  stone,  not  the  blue  hone  slate  used  for  brass 
work,  &c.  Flanders  brick  when  scraped  may  be  used  as  a  substitute  for 
Trent  sand,  but  being  contaminated  with  the  clay  required  hi  forming  the 
brick,  it  cuts  less  keenly  than  the  unmixed  sand. 

3. — SAND  PAPER  is  made  with  the  common  house  sand,  and  only  of  one  degree  of 
coarseness,  but  in  other  respects  exactly  like  glass  paper,  to  which  it  is  greatly 
inferior  ;  as  the  particles  of  sand  are  less  angular  and  cutting  than  those  of 
glass,  when  applied  upon  wood,  &c.,  but  on  metals  sand  paper  assumes  a 
character  intermediate  between  glass  paper  and  emery  paper. 

SAPPHIRE  has  been  selected  as  one  of  the  three  general  examples  of  lapidary 
work,  described  hi  this  catalogue,  namely  Alabaster  in  explanation  of  the 
mode  of  working  the  softest  stones,  and  other  allied  substances,  Carnelian  in 
explanation  of  the  modes  pursued  with  stones  of  greater  hardness  than 
Alabaster,  but  inferior  in  this  respect  to  Sapphire,  the  subject  of  the  present 
article.  Sapphires  are  alone  exceeded  in  hardness  by  the  diamond,  which 
last  is  pre-eminent  over  all  natural  substances,  in  point  of  hardness. 

The  previous  articles  on  Alabaster  and  Carnelian  may  with  advantage  be 
here  referred  to,  as  containing  much  general  information  upon  the  lapidary 
art,  and  which  will  be  more  fully  described  in  the  34th  Chapter  of  this 
volume ;  but  it  should  be  here  observed  that  the  harder  and  smaller  the 
gems  to  be  wrought,  the  harder  are  the  metallic  laps  or  mills  respectively 
employed  by  the  lapidary,  and  although  sapphire  may  in  truth  be  entirely 


AND    PROCESSES    FOR    GRINDING    AND    POLISHING.  1092 

wrought   by  the  method  employed  for  carnelian,  the  present  will  be  found 
the  more  usual,  as  well  as  the  more  economical  practice. 

As  gems  are  usually  retained  of  as  great  size  as  their  irregularities  of  sur- 
face will  admit,  sapphires  and  many  other  gems  are  seldom  reduced  in  size 
except  by  grinding,  or  as  it  is  more  commonly  called,  by  cutting  them. 
When  however  they  are  divided  it  is  more  commonly  done  by  cleavage  or 
splitting,  than  by  slitting  or  sawing,  and  which  process  when  resorted  to,  is 
effected  nearly  as  usual  with  an  iron  slicer  fed  with  diamond  dust,  and  lubri- 
cated with  brick  oil  ;  the  slicer  for  sapphires  is  however  very  much  smaller 
than  for  general  lapidary  works,  and  is  principally  met  with  in  the  hands  of 
watch  jewellers. 

Secondly,  the  lapidary  commonly  grinds  and  cuts  the  facets  on  sapphires 
upon  a  copper  lap,  supplied  with  diamond  dust  and  brick  oil,  which  cuts 
more  quickly  and  delicately  than  the  lead  mill  with  emery  ;  and  3rdly,  these 
gems  are  polished  upon  a  copper  lap  with  rottenstone  and  water,  the  tool 
being  jagged  after  the  manner  more  fully  described  under  the  head 
CARNELIAN. 

2. — The  practice  of  the  watch  jeweller  in  making  the  pivot  holes  for  watches  in 
ruby  and  sapphire,  is  described  in  the  first  volume  of  this  work,  pages 
178 — 9  :  Diamond  powder  is  used  throughout,  and  of  three  degrees  of  fine- 
ness, the  coarsest  on  copper  tools,  the  medium  on  glass,  and  the  finest  on 
pewter  tools  for  the  last  polish. 

Phillips  says  the  sapphire  has  obtained  several  names  amongst  mineralo- 
gists and  jewellers,  dependent  on  its  colour  and  lustre,  namely, — 

White  Sapphire,  when  transparent  or  translucent. 

Oriental  Sapphire)  when  blue. 

Oriental  Amethyst,  when  violet  blue. 

Oriental  Topaz,  when  yellow. 

Oriental  Emerald,  when  green. 

Oriental  Ruby,  when  red. 

Chatoyant,  or  Opalescent  Sapphire  with  pearly  reflections. 

Girasol  Sapphire,  when  transparent,  and  with  a  pale  reddish  or  pale 
bluish  reflection. 

ASTERIA  or  Star  Sapphire,  exhibits  6  milk-white  rays,  radiating  from  the 
center  of  an  hexagonal  prism,  and  placed  at  right  angles  to  its  sides.  The 
asteria  is  found  in  both  the  red  and  blue  varieties  of  Sapphire,  and  is  always 
cut  en  cdbochon  to  show  the  figure. 

All  the  above  Sapphires,  the  Chrysoberyl,  occasionally  the  Zircon  and 
some  others  of  the  gems,  are  cut  with  diamond  powder  and  polished  with 
rottenstone,  as  above  described. 

'  SARD. — A  variety  of  Chalcedony  that  is  wrought  by  the  lapidary  like  Carnelian. 
SARDONYX.— Idem. 

,  SATIN  STONE  or  fibrous  gypsum  is  treated  much  the  same  as  Alabaster,  but 

F  2 


1093  DESCRIPTIVE    CATALOGUE    OF    APPARATUS,    MATERIALS, 

requires  additional  tenderness.      See   ALABASTER,  article   3,  also  vol.   1, 
page  164. 

SAW  DUST  is  used  by  jewellers,  brass  finishers,  and  others,  in  drying  the  metals 
after  they  have  been  pickled  and  washed.  The  saw  dust  of  boxwood  is  pre- 
ferred for  jewellery  on  account  of  its  freedom  from  turpentine  or  resinous 
matter  ;  the  saw  dust  of  beech  wood  is  next  in  estimation. 

SCAGLIOLA,  Keene's  Cement,  and  other  factitious  marbles,  are  treated  nearly 
the  same  as  marble  ;  but  they  generally  require  less  labour  because  they  are 
accurately  moulded  into  form,  and  are  somewhat  softer  than  the  generality 
of  marbles  ;  but  when  the  materials  are  of  unequal  hardness  the  difficulty  of 
the  polishing  is  increased,  from  the  softer  parts  wearing  down  too  rapidly, 
and  leaving  the  surface  irregular. 

SERPENTINE,  when  in  large  pieces,  is  treated  like  marble  ;  when  the  serpentine 
is  in  small  pieces,  that  are  recent  and  soft,  the  lapidary  employs  much  the 
same  mode  that  he  would  in  grinding  and  polishing  Alabaster,  (see  article  3,) 
or  the  routine  for  Carnelian,  when  from  exposure  to  the  atmosphere  the 
serpentine  has  attained  its  greatest  degree  of  hardness. 

SHELLS.— On  reference  to  vol.  1,  pages  118 — 120,  a  few  remarks  on  the  descrip- 
tive characters  of  the  porcelanous  and  nacreous  shells  will  be  found.  Some 
of  these  shells  are  cut  through  to  show  their  internal  sections  or  structures, 
whilst  others  are  simply  polished  exteriorly  in  their  entire  states,  as  speci- 
mens of  natural  history,  or  for  their  intrinsic  beauty,  some  few  of  the 
shells  are  cut  up  in  the  manufacture  of  various  useful  and  ornamental  works. 
They  are  usually  treated  as  follows  : — 

1. — PORCELANOUS  SHELLS,  which  are  generally  univalve  or  single  shells,  such 
as  the  whelks,  limpets  and  cowries,  so  far  resemble  porcelain  or  enamel  as 
not  to  admit  of  being  otherwise  cut  than  with  the  apparatus  employed  by 
the  lapidary  ;  and  accordingly,  when  porcelanous  shells  are  divided  to 
exhibit  their  sections,  it  is  effected  by  the  Slicer,  with  Diamond  Powder. 

The  porcelanous  shells  do  not  in  general  require  the  coarser  or  grinding 
tools,  as  few  of  them  present  the  rough  coat  or  epidermis  of  the  nacreous 
shells,  and  it  is  therefore  only  commonly  needful  to  restore  or  increase  their 
natural  polish  with  the  list  or  brush  wheel  of  the  lapidary.  Putty  powder 
may  be  used,  but  rottenstone,  from  its  greater  hardness,  is  more  effective  on 
porcelanous  shells  :  of  course,  similar  wheels  running  in  a  vertical  plane, 
such  as  those  of  the  cutler  and  workers  in  horn  and  ivory,  may  be  also  used 
with  equally  good  effect. 
2. — NACREOUS  SHELLS,  which  are  generally  bivalve  shells,  such  as  those  of 
the  various  oysters,  muscles,  &c.,  are  thus  named  from  nacre,  the  French  for 
mother-of-pearl,  the  covering  of  the  ostrea  margantifera  of  the  Indian  seas. 
The  nacreous  shells  are  much  softer  than  the  porcelanous,  and  may  be  sawn, 
filed  and  turned  with  moderate  facility,  but  from  the  quantity  of  lime  they 
contain  they  feel  harsh  and  scratchy  under  the  tools. 


AND    PROCESSES    FOR    GRINDING    AND    POLISHING.  1094 

The  pearl  shell  is  much  employed  in  the  ornamental  art,  and  the  usual 
course  for  its  preparation  into  square,  angular  and  circular  plates,  and  cylin- 
drical pieces,  is  first,  with  saws  of  different  and  ordinary  kinds  ;  the  pieces 
are  then  roughly  shaped  on  the  edge  of  a  grindstone  turned  into  grooves, 
and  afterwards  smoothed  on  the  flat  side  of  the  stone  :  many  use  soap  and 
water  with  the  stone,  which  lessens  its  liability  to  become  clogged.  See  also 
vol.  1,  pages  119,  120. 

3. — PEARL  SHELL  IN  DETACHED  PIECES,  such  as  counters,  silk  winders,  &c., 
immediately  after  having  been  ground,  and  when  shaped  on  their  edges,  are 
smoothed  with  Trent  sand  or  pumice-stone  and  water,  on  a  buff  wheel  or 
hand  polisher,  and  are  finished  with  rottenstone. 

The  latter  powder,  although  sometimes  used  with  oil  or  water,  is  more 
frequently  moistened  with  a  little  sulphuric  acid,  nearly  or  quite  undiluted, 
this  produces  a  far  more  brilliant  polish,  which  may  possibly  arise  from  the 
partial  destruction  of  the  surface,  thus  developing  in  a  more  decided  man- 
ner the  striated  formation  of  the  pearl  shell,  and  to  which  peculiarity  of 
structure  its  variegated  lustre  is  ascribed. 

4. — PEARL  WORKS  COMBINED  AS  IN  BOXES  are  most  generally  reduced  to  a  flat 
surface  by  filing  and  scraping.  Mr.  Vanham  says  that  first  pumice-stone 
and  then  putty  powder  are  used  on  buff  sticks  with  water,  and  the  final 
polish  is  given  with  a  buff  stick  and  rottenstone  moistened  with  sulphuric 
acid,  this  mode  is  available  for  inlaid  works  with  gold  or  silver,  but  not 
for  those  having  tortoiseshell  or  other  substances  that  would  be  attacked  by 
the  acid.  The  buff  stick  is  expeditious,  but  for  very  flat  surfaces,  a  flat  deal 
stick  covered  with  one  layer  of  linen  rag  is  preferable  although  slower. 

5. — TURNED  WORKS  in  general  only  require  fine  emery  paper,  and  then  rotten- 
stone  on  woollen  rag  with  sulphuric  acid,  but  oil  may  be  used  instead  of  the 
latter. 

6. — PEARL  HANDLES  FOR  RAZORS. — The  Sheffield  manufacturers  slightly  rivet 
the  handles  together  in  pairs,  after  which  they  are  1st  scraped,  2ndly  "  sand 
luffed  "  on  the  wheel  with  Trent  sand  and  water,  3dly,  "  gloss  luffed  "  on  the 
wheel  with  rottenstone  and  oil,  or  sometimes  with  dry  chalk  rubbed  on  the 
same  wheel,  and  4thly  they  are  « handed  up"  or  polished  with  dry  rotten- 
stone  and  the  naked  hand. 

7. — PEARL  SHELL,  when  polished  by  the  lapidary,  is  treated  in  the  mode  followed 
with  ALABASTER.  See  article  3. 

8. — SHELL  CAMEOS. — A  very  suitable  material  for  cameos  is  found  in  the  various 
conch  shells  or  Strombs,  the  substance  of  which  consists  of  two  distinct  layers 
of  different  colours,  textures  and  hardness,  and  which  may  be  considered 
respectively  to  partake  of  the  nature  of  nacreous  and  porcelanous  shells, 
the  chemical  compositions  of  which  were  noticed  in  vol.  1,  page  118.  The 
outer  coat  or  layer  in  the  most  suitable  specimens  of  conch  shells  is  nearly 
colourless,  of  uniform  texture,  and  like  that  on  the  nacreous  shells  admits  of 
being  readily  operated  upon  by  steel  cutting  tools,  and  which  may  be  made 
to  produce  a  smooth  and  well-finished  surface,  this  outer  layer  is  therefore 


1095  DESCRIPTIVE    CATALOGUE    OF    APPARATUS,    MATERIALS, 

suited  for  the  carved  parts  of  cameos,  the  ground  being  formed  of  the  under 
layer  of  the  shell,  which  in  the  most  suitable  kinds  is  of  a  dark  colour,  and 
allied  to  the  porcelanous  shells,  being  somewhat  brittle  and  so  hard  and 
compact  as  not  to  admit  of  being  readily  cut  with  steel  tools. 

The  best  kind  of  conch  shell  for  carving  into  cameos  is  found  on 
the  Southern  coast  of  America,  and  also  on  the  coast  of  the  West  India 
Islands,  and  commonly  known  as  the  "  Hack  conch ;  "  in  these  shells  the 
contrast  of  colour  is  the  most  decided,  the  under  layer  being  very  dark  or 
nearly  black,  especially  in  the  old  or  full  grown  shells,  which  are  the  hardest 
and  most  compact,  and  also  possess  the  greatest  amount  of  the  white  or 
outer  layer,  the  part  to  be  carved.  In  the  pink  conch  shell  the  contrast  of 
colour  is  not  so  great,  and  as  it  does  not  at  all  resemble  the  onyx  in  which 
antique  cameos  were  cut,  it  is  but  little  used  for  the  best  works  ;  never- 
theless, some  very  beautiful  specimens  of  carving  on  the  pink  conch  shell 
are  to  be  met  with,  and  the  delicacy  of  the  colours  gives  a  very  pleasing 
effect. 

The  most  suitable  shell  having  been  selected  it  is  cut  into  pieces  of  the 
required  forms  for  the  cameos  ;  this  process,  which  must  be  cautiously  per- 
formed, is  best  effected  by  means  of  the  slitting  mill  fed  with  diamond 
powder,  described  in  the  chapter  on  Lapidary  Work,  but  the  cutting  may 
be  also  effected  with  a  blade  of  iron  or  steel,  such  as  a  thin  table  knife 
blade  notched  to  form  teeth,  and  fed  with  emery  and  water,  a  process 
similar  to  that  by  which  the  stone  mason  cuts  slabs  of  freestone  and  marble 
with  a  smooth  blade  of  iron  fed  with  sand  and  water. 

The  piece  of  shell  having  been  cut  out  is  next  carefully  ground  to  the 
general  form  of  the  cameo,  as  square,  lozenge,  elliptical  or  other  shape,  upon 
an  ordinary  grindstone,  the  face  and  back  of  the  shell  being  also  levelled  and 
reduced  to  the  appropriate  thickness.  A  slip  of  Turkey  oilstone  may  be 
used  with  advantage  to  give  the  last  finish  to  the  edges  of  the  shell  after  the 
upper  white  layer  has  been  removed  from  it,  for  when  the  shell  has  lost 
the  support  of  the  white  layer,  it  will  be  found  that  the  coarse  cut  of  the 
grindstone  will  fill  it  with  minute  cracks,  which  frequently  spread  over  the 
surface  after  the  cameo  has  been  some  time  finished. 

Having  prepared  a  piece  of  shell  of  the  desired  form  and  thickness  it  is 
next  cemented  on  a  block  of  wood  about  3  inches  diameter,  or  of  a  con- 
venient size  to  be  grasped  firmly  in  the  hand  ;  care  should  be  taken  to  place 
the  piece  of  shell  level  and  near  the  center  of  the  block,  in  order  that  all 
parts  of  the  cameo  may  be  operated  upon  with  equal  facility.  Now  sketch 
with  a  pencil  the  contour  of  the  subject  to  be  carved,  and  follow  this  pencil- 
mark  with  a  scratch  point ;  having  removed  the  surrounding  white  substance 
by  means  of  files  and  gravers  proceed  to  develope  the  figure  by  the  use  of 
smaller  tools.  A  very  convenient  form  of  carving  tool  for  this  purpose 
may  be  made  of  pieces  of  steel  wire  about  6  or  8  inches  long,  flattened  at  the 
ends  and  hardened  ;  they  are  lastly  ground  to  an  angle  of  about  45  degrees, 


AND    PROCESSES    FOR    GRINDING    AND    POLISHING.  1096 

and  carefully  sharpened  on  an  oilstone.  The  largest  tools  may  be  made  of 
wire  about  ^  of  an  inch  diameter  ;  smaller  wire  will  serve  for  tools  of  a 
medium  size,  but  for  the  smallest  tools  an  ordinary  darning  needle  left  quite 
hard,  and  ground  to  the  same  angle,  when  inserted  in  a  wooden  handle,  will 
be  found  very  useful  in  deepening  the  finer  lines.  The  advantage  of  this 
form  of  tool  consists  in  the  absence  of  any  angles  that  would  be  liable  to 
scratch  the  work,  and  a  tool  thus  formed  admits  of  being  used  either  as  a 
gouge,  or  as  a  chisel,  according  as  the  flat  or  round  side  is  brought  to  act 
on  the  work. 

To  guide  the  tool  in  the  act  of  cutting,  the  left  hand  should  grasp  the  block 
upon  which  the  cameo  is  cemented,  the  thumb  being  placed  close  to  the 
cameo  ;  the  tool  held  in  the  right  hand  should  be  so  rested  against  the  thumb 
of  the  left  hand  as  to  form  a  fulcrum,  upon  which  the  tool  may  be  moved  as 
a  lever  in  short  arcs  of  the  circle,  with  a  scraping  action  which  removes  the 
material  as  a  powder,  care  being  taken  that  every  cut  is  made  obliquely 
downwards  towards  the  black  ground  ;  should  any  of  the  cuts  be  made 
towards  the  surface,  or  even  parallel  therewith,  there  would  be  danger  that 
small  pieces  would  be  chipped  off,  and  which  would  be  destructive  to  the 
cameo. 

As  in  all  other  processes  of  producing  form  by  reduction,  the  general 
shape  should  be  first  wrought  with  care  to  leave  every  projection  rather  in 
excess,  to  be  gradually  reduced  as  the  details  and  finish  of  the  work  are 
approached.  To  render  the  high  parts  more  distinct  during  the  process  of 
carving,  it  will  be  found  convenient  to  mark  them  slightly  with  a  black  lead 
pencil.  Throughout  the  cutting  great  caution  should  be  observed,  that  in 
removing  the  white  thickness,  the  dark  ground  is  not  damaged,  as  the 
natural  surface  of  the  dark  layer  is  far  superior  to  any  that  can  be  given 
artificially  ;  indeed,  should  the  ground  be  broken  up  at  one  part,  it  would  be 
requisite  from  its  lamellar  structure  to  remove  the  entire  scale  or  lamina 
from  the  whole  surface,  a  process  that  will  be  found  very  tedious,  and  much 
more  difficult  than  the  separation  of  the  white  from  the  black  thickness. 

In  order  that  the  finished  cameo  may  possess  a  distinct  outline  at  all 
points  of  view,  it  is  desirable  to  adopt  the  system  followed  in  antique  cameos, 
namely,  to  leave  all  the  edges  of  the  figure  quite  square  from  the  ground,  and 
not  gradually  rounded  down  to  the  dark  surface  ;  should  this  latter  method 
be  followed,  it  will  be  found  that  the  outline  is  in  many  places  undefined, 
owing  to  the  colour  of  the  white  raised  figure  of  the  cameo  gradually  merging 
into  that  of  the  dark  ground  ;  this  evil  is  entirely  avoided  by  leaving  the 
extreme  edge  of  the  figure  quite  square,  for  about  the  thickness  of  one- 
fiftieth  of  an  inch. 

The  surface  of  the  cameo  should  be  finished  as  nearly  as  possible  with  the 
cutting  tools,  as  all  polishing  with  abrasive  powders  is  liable  to  remove  the 
sharp  angles  of  the  figures,  and  deteriorate  the  cameo  by  leaving  the  form 
undefined.  When,  however,  the  work  has  been  finished  as  smooth  as  possible 


1097  DESCRIPTIVE    CATALOGUE    OF    APPARATUS,    MATERIALS, 

with  the  cutting  tools,  the  final  polish  may  be  given  with  a  little  putty 
powder  used  dry,  upon  a  moderately  stiff  tooth  brush,  applied  with  care,  and 
rather  to  the  dark  ground  than  to  the  carved  surface  :  this  is  the  concluding 
process  ;  after  which  the  cameo  is  ready  for  removal  from  the  block  prior  to 
mounting. 

SILEX  is  the  basis  of  tripoli,  sandstones,  sand  and  some  other  polishing  powders. 
It  constitutes  from  about  65  to  98  per  cent,  of  these  substances,  and  is  the 
fourth  or  fifth  of  the  polishing  materials  in  the  order  of  hardness, — silex 
being  preceded  by  carbon  and  alumina,  and  probably  by  the  oxides  of  iron 
and  tin.  See  page  1029  of  this  volume. 

Dutch  rush  and  charcoal  owe  their  abrasive  qualities,  and  the  enamel  of 
teeth  its  hardness,  to  the  silex  they  respectively  contain. 

See  also  CRYSTAL  and  QUARTZ. 

SILVERSMITHS'  work,  after  having  been  filed  is  generally  rubbed,  1st  with  a 
lump  of  pumice-stone  and  water,  2ndly  with  a  slip  of  water  of  Ayr  stone  and 
water,  3dly  a  revolving  brush  with  rottenstone  and  oil,  4thly  an  old  black 
worsted  stocking  with  oil  and  rottenstone,  and  5thly  it  is  finished  with  the 
hand  alone,  the  deep  black  lustre  being  given  with  rouge  of  great  fineness. 
The  corners  and  edges  are  often  burnished  with  a  steel  burnisher,  which  is 
lubricated  with  soap  and  water  if  at  all. 

In  this  case  and  in  all  others  of  polishing  with  the  naked  hand,  it  is  gene- 
rally found  that  women  succeed  better  than  men,  and  that  some  few,  from 
the  peculiar  texture  and  condition  of  the  skin,  greatly  excel  in  the  art  of 
polishing.  The  skin  should  be  soft  and  very  slightly  moist,  as  the  polishing 
powder  then  attaches  itself  conveniently,  and  there  is  just  sufficient  adhesion 
between  the  hand  and  work  to  make  the  operation  proceed  rapidly.  A 
dry  hand  becomes  hard  and  horny,  and  is  liable  to  scratch  the  work,  and 
excess  of  moisture  is  also  objectionable,  as  the  hand  is  then  too  slippery. 
2. — THE  PLATED  REFLECTORS  FOR  LIGHT-HOUSES  are  cleaned  with  rouge,  which  is 
dusted  on  from  a  muslin  bag,  and  rubbed  over  them  with  a  clean  dry  wash- 
leather. 

A  thin  film  of  oxide  will  nevertheless  occasionally  form  on  the  surface  of 
the  reflector,  and  this  is  removed  with  a  piece  of  leather,  with  rouge  moist- 
ened with  spirits  of  wine,  which  dissolves  the  oxide,  after  which  the  dry 
rubber  is  applied  as  above. 

SKIVE. — The  iron  lap  used  by  the  diamond  polishers  in  finishing  the  facets  of 
diamonds  for  jewellery.  The  skive  is  charged  with  fragments  of  diamond 
powder  that  are  burnished  into  its  surface.— See  DIAMOND,  also  page  176, 
vol.  1. 

SLATE. — The  ordinary  slate  used  for  building  purposes  does  not  admit  of  being 
highly  polished,  but  it  is  rubbed  smooth,  first  with  an  iron  plate  fed  with 


AND    PROCESSES    FOR    GRINDING    AND    POLISHING.  1098 

sharp  river  sand  and  water,  and  then  with  lumps  of  gritstones,  of  which 
two  or  three  kinds  gradually  finer  one  than  the  other,  are  also  used  with 
water.  The  rubstones  employed,  depend  principally  on  their  relative  abund- 
ance in  the  respective  districts. 

A  lump  of  pumice-stone  leaves  a  grain  on  slate  suitable  for  writing  upon, 
and  the  greyness  is  removed  either  by  a  slight  rub  of  oil,  or  what  is  better  a 
wash  of  common  writing  ink  allowed  to  dry  on.  A  disk  of  slate  cemented  to  a 
wood  chuck  is  useful  to  the  amateur  for  receiving  in  the  lathe  rough  sketches 
of  eccentric  patterns,  and  slate  also  serves  for  drawing  boards. 

As  noticed  in  vol.  1,  page  165,  slate  has  been  recently  employed  for  chimney 
pieces,  internal  decoration  and  furniture,  hi  which  case  it  is  rubbed  smooth, 
then  japanned  like  black  and  other  marbles,  and  also  of  all  colours  and 
devices,  after  the  manner  of  tea  trays  ;  when  the  objects  have  been  baked  to 
harden  the  japan  they  are  first  smoothed  with  pumice-stone,  and  then 
polished  with  rottenstone,  after  the  ordinary  mode  described  under  JAPANNED 
WORKS. 

SLICER.— See  SLITTING  MILL. 

SLITTING  MILL  or  the  Slicer,  is  a  very  thin  sheet-iron  disk,  the  edge  of  which  is 
charged  with  diamond  powder,  and  lubricated  with  brick  oil.  The  slicer  is 
the  circular  saw  of  the  lapidary.  See  the  chapter  on  LAPIDARY  WORK. 

SNAKE  STONE.— See  HONE  SLATES,  article  3. 

SOAP  AND  WATER  have  been  proposed  by  Mr.  Reveley,  to  be  used  on  hones 
instead  of  oil,  in  setting  razors  and  other  fine  instruments,  as  being  more 
cleanly  and  effective. 

The  hone  is  to  be  wiped  clean  with  a  wet  sponge,  and  the  lump  of  soap  also 
wetted,  is  to  be  rubbed  on  until  it  produces  a  thin  lather,  which  is  to  be 
sponged  off  when  the  hone  is  laid  by — Trans.  Soc.  of  Arts,  vol.  xxxix.  p.  137. 

SOFT  WOOD.— See  WOOD. 

SPECULAR  IRON  ORE.— See  OXIDE  OF  IRON,  articles  5  and  6. 

SPECULUM  METAL. — The  mode  of  grinding  and  polishing  this  alloy  will  be 
noticed  in  Chap.  XXXIII. 

SPHERES. — Mr.  Henry's  Guy's  method  of  grinding  spheres  will  be  described  in 
Chap.  XXXIII.  Sect.  4.  See  also  the  article  MARBLES  FOR  CHILDREN,  in 
this  Catalogue. 

STEATITE,  especially  when  first  raised,  is  a  soft  unctuous  magnesian  mineral,  and 
is  thence  called  soapstone,  but  like  Potstone,  and  Serpentine,  which  it 
nearly  resembles  in  its  constituent  parts,  it  becomes  considerably  harder  by 


1099  DESCRIPTIVE    CATALOGUE    OF    APPARATUS,    MATERIALS, 


exposure  to  the  air.  Steatite  when  recent,  may  be  treated  by  the  method 
practised  in  Germany  with  POTSTONE,  (which  see  on  page  1087,)  and  when 
indurated,  by  the  same  routine  that  is  employed  for  alabaster  by  the  lapidary. 
Many  of  the  Chinese  idols  and  other  figures,  are  carved  in  Steatite,  which 
has  thence  been  called  Figure  Stone.  See  vol.  1,  page  166. 

STEEL. — The  parts  of  Machinery  made  in  steel,  are  polished  as  described  in  the 
general  article  MACHINERY,  in  this  Catalogue,  page  1072. 

STRAGGLING. — A  term  indicating  the  mode  of  dressing  the  surfaces  of  grind- 
stones, which  is  fully  described  under  WHEELS,  article  16. 

SURFACES. — The  principal  modes  of  grinding  plane  surfaces  are  described  in 
Chap.  XXXIII.  Sect.  1. 

TIN  is  seldom  polished  except  when  in  the  form  of  tin-plate,  for  which  purpose, 
rottenstone  and  oil,  or  whitening  and  oil  may  be  used,  dry  whiting  being 
lastly  applied  to  remove  the  grease. 

Works  in  solid  tin  are  occasionally  made  by  pewterers,  and  polished  the 
same  as  that  useful  alloy.  See  PEWTER. 

TIN,  OXIDE  OF.— See  PUTTY  POWDER. 

TOPAZ  ;  of  the  Brazilian  Topazes,  there  are  the  yellow,  which  is  best  known,  the 
blue,  and  the  white,  the  latter  being  more  commonly  called  the  Mina  Nova. 
The  Brazilian  Topazes  are  worked  like  Carnelian,  the  Oriental  Topaz,  which 
is  in  fact  a  yellow  variety  of  Sapphire,  is  treated  like  other  Sapphires,  and  is 
cut  into  facets  with  diamond  powder  and  polished  with  rottenstone,  as  more 
fully  described  under  the  head  SAPPHIRE.  The  difference  in  hardness  of  the 
two  gems  is  satisfactorily  accounted  for  by  their  analysis,  as  the  Brazilian 
Topaz  contains  about  50  per  cent,  of  alumine,  the  Oriental  about  98  per  cent, 
of  alumine  ;  this  substance  being  next  in  hardness  to  the  diamond. 

TORTOISESHELL. — The  covering  of  the  Testudo  imbricata,  and  on  the  working 
of  which  the  reader  is  referred  to  vol.  1,  pages  126 — 135,  is  usually  polished 
after  one  of  the  following  modes  : — 

1. — TORTOISESHELL  HANDLES  for  razors  and  penknives,  combs,  spectacle  frames, 
and  many  similar  works,  after  they  have  been  sawn  out  and  moulded  into 
form,  (see  vol.  1,  page  130,)  are  smoothed  with  afloat  or  single  cut  file  techni- 
cally known  as  a  guannet,  (see  vol.  2,  page  838,)  and  then  shaved  or  scraped 
smooth  with  a  scraper  like  that  used  by  joiners.  Cutlers  often  use  an  old 
razor  blade  the  edge  of  which  has  been  sharpened  at  right  angles,  by  placing 
the  blade  perpendicularly  on  the  oilstone. 

The  works  are  then  very  sparingly  polished  on  a  wheel  covered  with  thick 
buff  leather,  such  as  the  bull  neck,  or  sea  cow,  and  fed  with  calcined  Trent 
sand  and  oil,  (see  article  on  HORN,  page  1067,)  and  they  are  finished  on  a 
similar  wheel  supplied  with  rottenstone  and  oil,  occasionally  the  latter  wheel 


AND    PROCESSES    FOR    GRINDING    AND    POLISHING.  1100 

is  alone  used.  Razor  handles  and  some  other  works  are  often  handed  uup, 
or  finished  with  the  naked  hand  and  dry  rottenstone,  and  works  required  to 
be  very  nice  and  flat  are  more  generally  treated  as  follows  : — 

2. — FLAT  WORKS  IN  TORTOISESHELL,  such  as  card  and  needle  cases  and  others  that 
require  to  be  kept  flat,  are  floated  and  scraped  as  above,  and  Mr.  W.  Vanham 
before  referred  to  says,  that  he  afterwards  successively  employs  pumice- 
stone,  putty-powder  and  rottenstone  on  three  different  buff  sticks,  and  all 
generally  with  water  but  sometimes  with  oil,  as  the  treatment  varies  accord- 
ing to  the  material  inlaid  in  the  tortoiseshell,  which  is  lastly  finished  with  the 
hand  and  rottenstone  or  whiting.  When  the  works  have  mouldings  and 
sharp  edges  that  would  be  rounded  by  the  buff  stick,  the  same  materials  are 
used  on  slips  of  wood  filed  to  the  appropriate  forms. 

3. — TORTOISESHELL  WHEN  TURNED  IN  THE  LATHE  is  usually  smoothed  with  fine 
glass  or  emery  paper,  and  finished  with  rottenstone  and  oil,  on  linen  or 
woollen  rag. 

TOUCHSTONE  is  a  compact  black  basalt  or  Lydian  stone,  of  a  smooth  and  uniform 
nature,  and  is  used  principally  by  goldsmiths  and  jewellers  as  a  ready  means 
of  determining  the  value  of  gold  and  silver  by  the  touch,  as  it  is  termed — 
that  is,  by  first  rubbing  the  article  under  examination  upon  the  stone,  its 
appearance  forms  some  criterion  ;  and,  as  a  further  test,  a  drop  of  acid,  of 
known  strength,  is  let  fall  upon  it,  and  its  effect  upon  the  metal  denotes  its 
value. 

TRENT  SAND.— See  SAND. 

TRIPOLI,  according  to  Phillips,  is  an  earth  of  a  grey  yellow  or  red  colour,  used  in 
polishing,  that  was  first  introduced  from  Tripoli  in  Africa,  whence  its  name, 
but  it  is  found  in  France  and  elsewhere,  and  is  said  to  contain  nearly  90 
per  cent,  of  silex. 

2.  RED  TRIPOLI  has  been  largely  prepared  from  a  brick  earth  found  near  Battle 

in  Sussex.  When  burned  in  lumps  it  is  nearly  as  heavy  as  emery  stone, 
after  which  it  is  ground  and  sifted,  and  presents  the  appearance  of  crocus, 
but  is  coarser  and  is  used  for  similar  but  inferior  purposes. 

A  Red  Tripoli  prepared  by  calcining  and  pulverising  Clwnch  or  Curl  Stone, 
found  in  the  coal  and  iron  districts  of  Staffordshire,  &c.  is  highly  recom- 
mended by  Mr.  Gill.  See  the  articles  on  the  OXIDES  OF  IRON. 

3.  YELLOW  TRIPOLI,  sometimes  called  French  Tripoli,  is  employed  for  polishing 

generally,  and  amongst  other  substances  for  light-coloured  hardwoods  that 
would  be  stained  by  the  absorption  of  darker  powders  into  their  pores.  A 
large  quantity  of  fine  yellow  tripoli  was  obtained  in  digging  the  canal  in 
the  Regent's  Park,  London  ;  some  additional  particulars  are  given  on  this 
subject  at  the  conclusion  of  the  article  on  VARNISHED  WORKS. 

TURKEY  OILSTONE.— See  OILSTONE. 


1101  DESCRIPTIVE    CATALOGUE    OF    APPARATUS,    MATERIALS, 

TURQUOISE. — The  Oriental  Calaite,  or  Turquoise,  is  a  comparatively  soft  gem, 
found  in  the  mountainous  districts  of  Khorassan  in  Persia,  those  of  a  dark 
blue  colour  being  the  most  esteemed.  They  are  somewhat  rarely  engraved 
as  seals,  but  are  mostly  used  by  the  Persians,  nearly  of  their  natural  forms,  for 
ornamenting  bridles,  the  handles  of  scimitars,  &c.,  as  the  Orientals  remove 
in  general  but  little  of  the  weight  of  gems  in  cutting  and  polishing  them, 
which  they  effect  on  corundum  wheels,  although  they  are  well  acquainted 
with  the  use  of  diamond  powder  as  an  abrasive  for  such  works  as  require  it. 
In  Europe  the  turquoise  is  generally  cut  and  polished  by  the  method 
pursued  with  alabaster  and  other  soft  and  rounded  stones. 

TURTLESHELL  is  worked  and  polished  the  same  as  TORTOISESHELL,  which  see. 

VARNISHED  WORKS  of  the  finest  kinds,  such  as  the  wood  work  of  harps,  are 
thus  treated.  The  wood  is  covered  with  about  six  layers  of  the  white  hard 
varnish,  and  allowed  thoroughly  to  dry  between  each,  this  entirely  fills  the 
pores  of  the  wood  ;  the  face  is  then  rubbed  quite  smooth  with  fine  glass 
paper.  The  ornamental  painting  is  then  done,  after  which  about  eight  or  ten 
coats  more  of  varnish  are  laid  on,  and  at  every  third  coat  the  surface  is 
rubbed  with  fine  glass  paper  to  remove  the  brush  marks. 

When  all  the  varnish  is  put  on,  and  has  become  hard,  the  surface  is  rubbed 
with  fine  pumice-stone  powder  and  water  on  woollen  rags,  the  work  is  allowed 
to  stand  for  a  day  or  two,  and  is  then  polished  with  yellow  tripoli  and  water, 
after  which  it  is  washed  quite  clean  with  a  sponge,  and  wiped  dry  with  a  clean 
wash  leather. 

The  varnish  is  now  touched  at  a  few  places,  with  the  finger  smeared  with 
fine  rendered  tallow,  which  is  then  thoroughly  rubbed  all  over  with  the  ends 
of  the  fingers  ;  clean  wheat  flour  is  dusted  over  the  work,  and  also  well 
rubbed  in  with  the  fingers  ;  and  after  the  removal  of  the  flour,  the  surface 
is  slightly  rubbed  with  a  clean  old  silk  handkerchief,  which  completes  the 
splendid  lustre  given  to  these  instruments. 

It  should  be  observed  that  the  rottenstone  of  commerce  is  sometimes 
ground  very  fine  with  a  stone  muller  before  use,  and  so  is  likewise  the 
tripoli.  The  tripoli  used  by  the  Messrs.  Erats,  from  whom  these  par- 
ticulars were  gathered,  was  obtained  from  the  earth  removed  in  digging  the 
canal  hi  the  Regent's  Park,  London ;  the  dry  lumps  when  cleared  from  the 
clay  by  which  they  are  surrounded,  are  of  a  light  brown  yellow,  and  as  hard 
as  a  stone,  so  as  to  require  to  be  crushed  with  a  hammer  previously  to  being 
ground. 

WASHING  or  the  separation  of  powders  into  different  degrees  of  fineness  by 
washing  over  or  elutriation. — On  the  advantages  of  the  careful  separation  of 
the  polishing  powders  some  remarks  were  offered  in  the  introduction  to  this 
division  of  the  work  (see  page  1031)  ;  the  practice  of  washing,  which  is  within 
the  reach  of  every  one,  is  described  in  this  Catalogue  under  the  head  EMERY, 
articles  3,  4,  5  and  6. 


AND    PROCESSES    FOR    GRINDING    AND    POLISHING.  1102 

The  author  has  been  in  the  habit  of  washing  some  others  of  the  polishing 
powders,  but  generally  into  two  sizes  only  of  each  ;  the  times  employed  for 
their  respective  depositions,  which  are  somewhat  influenced  by  the  specific 
gravities  of  the  substances  are  subjoined. 

POWDER.  No.  1.  No.  2. 

Chalk             .            .  .             .1  minute  2  minutes 

Crocus               .            .  .  10  seconds  30  seconds 

Oilstone  Powder        .  .             .  30        „  3  minutes 

Pumice-stone  Powder      .  .  30        „  3       „ 

Rottenstone                 .  .             ,  30        „  3       „ 

Tripoli     .  .       .  30        „  1       „ 

Washing  is  constantly  employed  in  metallurgy,  for  the  separation  of  the 
metallic  particles  from  the  earthy  matters  in  the  pounded  ores ;  in  the 
manufacture  of  porcelain  for  the  separation  of  the  coarse  and  large  particles 
from  the  fine  clay,  and  prepared  flint,  therein  used,  and  in  the  preparation 
of  polishing  powders  and  some  drugs. 

rATCHWORK.— As  regards  the  parts  in  steel,  see  MACHINERY,  article  13,  and 
the  parts  in  brass  see  BRASS,  article  6. 

WATER  OF  AYR  STONE.— See  HONE  SLATES,  article  3. 
WELCH  CLEARING  STONE.— See  HONE  SLATES,  article  10. 

WHALEBONE. — Some  of  the  applications  of  this  peculiar  substance  are  noticed 
in  vol.  1,  pages  135-6.  To  polish  whalebone  it  is  scraped  with  steel  scrapers 
or  pieces  of  window  glass,  rubbed  with  emery  paper,  and  then  with  woollen 
cloth  supplied  with  tripoli  or  rottenstone.  The  polishing  lathe  is  also  used 
for  whalebone,  which  is  then  treated  like  horn  or  tortoiseshell. 

rHEELS. — In  almost  every  branch  of  the  manufacturing  and  mechanical  arts, 
the  processes  of  abrasion  are  advantageously  fulfilled  by  rotatory  motion 
applied  to  various  grinders  and  polishers.  These  are  generally  circular 
disks,  made  of  a  great  variety  of  substances,  and  are  for  the  most  part  fed 
with  abrasive  powders.  Most  of  these  apparatus,  with  the  exception  prin- 
cipally of  the  grindstone,  are  known  by  the  cutler  and  the  tool  maker  as 
wheels  ;  by  the  mechanician  as  laps,  by  the  lapidary  as  mills,  by  the  optician 
as  tools,  and  also  by  many  other  conventional  names  ;  the  first  name,  or 
WHEELS,  has  been  selected  for  the  title  of  this  article  as  being  the  most 
general.  A  few  words  will  be  first  offered  on  the  principal  modes  in  which 
these  wheels  are  employed. 

1. — GENERAL  MECHANICAL  ARRANGEMENTS. — Cutlers  and  tool  makers  place  the 
axes  of  the  wheels  horizontally,  and  employ  both  for  the  grindstone  and 
the  polishing  wheels  the  same  framework  or  apparatus.  Mechanicians 
frequently  employ  nearly  the  same  arrangement  as  cutlers  and  tool  makers, 
and  in  some  few  cases  mount  the  laps  and  wheels  as  adjuncts  to  the  lathe. 


1103  DESCRIPTIVE    CATALOGUE    OF    APPARATUS,    MATERIALS, 

Seal  Engravers  always  use  a  small  lathe  mandrel,  to  which  their  delicate 
grinders  are  attached.  Lapidaries,  unlike  the  above-named  artizans,  mostly 
place  the  axes  of  their  mills  vertically,  and  frequently  drive  them  by  the  left 
hand,  as  will  be  explained.  Opticians  fix  their  spherical  tools  for  grinding 
and  polishing  lenses,  horizontally,  on  the  top  of  a  fixed  post,  and  rub  the 
lenses  or  specula  upon  the  same  with  an  elliptical  motion  given  by  the  hands, 
and  they  continually  walk  round  the  post,  to  change  the  direction  in  which 
the  grinder  and  tool  successively  meet.  See  Chap.  XXXIII. 

These  and  other  mechanical  arrangements,  will  however  be  touched  upon 
in  the  course  of  the  chapters  immediately  following,  and  therefore,  it  is 
intended  at  this  place  principally  to  direct  attention  to  the  abrasive  appa- 
ratus, and  which  will  be  classed  under  seven  heads  namely  : — 

A. — Wheels  of  Natural  Stone  such  as  Grindstones. 

B. — Wheels  of  Factitious  Stone,  or  Composition  Wheels. 

C. — Wheels  of  Metal,  or  Metallic  Laps. 

D.— Wheels  of  Wood,  or  Glaze  Wheels. 

E. — Wheels  of  Leather,  or  Buff  Wheels. 

F.— Wheels  of  Cloth,  or  Cloth  Wheels. 

G. — Wheels  of  Bristles,  or  Wire,  or  Brush  Wheels. 

In  every  case  but  the  first,  the  cement,  metal,  wood,  leather,  cloth  or 
bristles,  are  to  be  viewed  solely  as  the  vehicles  or  carriers  by  which  the 
abrasive  matters  or  powders  are  applied.  And  in  speaking  of  these  appa- 
ratus, their  structure  will  be  first  noticed,  and  some  observations  on  the 
modes  of  using  them  and  keeping  them  in  order,  will  be  then  subjoined. 
The  first  of  the  seven  sections  or  the  natural  grindstones  will  be  now  consi- 
dered under  their  principal  although  varied  features. 

SECTION  A. — WHEELS  OF  NATURAL  STONE,  SUCH  AS  GRINDSTONES. 

2. — The  reader  is  referred  to  the  article  GRITSTONE,  for  the  description  of  the 
principal  varieties  of  the  sandstones  or  gritstones  used  in  the  mechanical 
arts  for  various  purposes,  the  most  important  of  which  uses  is  the  grinding 
of  various  cutting  tools  ;  indeed  the  removal  of  the  grindstones  from  our 
workshops,  would  be  an  almost  insuperable  loss.  The  principal  modes  of 
employing  grindstones  will  be  now  described. 

3. — GRINDSTONES  USED  BY  HAND. — In  the  most  primitive  method  the  tools  to  be 
ground  are  simply  rubbed  on  the  quiescent  stone,  as  stonemasons  and  others 
whet  their  chisels  on  the  foot  pavement,  after  the  manner  of  sharpening  a 
tool  upon  a  hone  ;  or  smaller  slabs  of  gritstones  are  employed  after  the 
manner  of  the  butcher's  steel,  in  fact  as  in  whetting  a  scythe  with  the 
rubstone. 

It  is  however  very  far  more  usual  to  fashion  the  grindstone  as  a  thick 
disk,  or  very  short  cylinder,  and  to  perforate  it  with  a  square  central  hole 
or  eye,  for  the  iron  axis  upon  which  the  stone  is  mounted  and  put  in  rota- 
tion, as  described  in  the  succeeding  paragraphs. 


AND    PROCESSES    FOR    GRINDING    AND    POLISHING. 


1104 


4. — GRINDSTONES  MOVED  BY  WINCH-HANDLES. — These  present  the  greatest 
degree  of  simplicity  of  all  rotary  grindstones,  and  must  be  familiar  to  almost 
every  one  ;  when  the  stone  does  not  exceed  about  one  foot  in  diameter,  it  is 
commonly  mounted  on  the  upper  edges  of  the  little  wooden  box  or  trough, 
which  serves  both  to  support  the  pivots  of  the  axis  on  which  the  stone 
revolves,  and  to  contain  the  water  with  which  it  is  moistened.  The  one 
extremity  of  the  spindle  is  squared  for  the  winch-handle,  the  central  part 
is  squared  for  the  convenience  of  wedging  on  the  stone  with  wooden 
wedges,  and  there  are  cylindrical  necks  or  pivots  on  the  axis,  the  bearings 
for  which  are  sometimes  of  hard  wood  such  as  lignum  vitse,  or  far  better 
of  metal. 

In  the  most  common  form,  two  iron  staples  which  surround  the  pivots  are 
simply  driven  into  the  top  edges  of  the  wooden  trough  ;  in  the  best  form, 
the  trough  and  bearings  are  both  in  metal,  and  there  is  a  small  bar  or  rest 
parallel  with  the  axis  for  supporting  the  tool  which  is  held  in  the  right  hand, 
whilst  the  stone  is  turned  with  the  left.  The  stones  thus  mounted  some- 
times measure  nearly  as  much  as  20  inches  in  diameter,  and  are  used  by 
general  artizans  for  small  tools  and  also  by  opticians  for  fitting  in  the  lenses 
of  spectacles. 

5. — ORDINARY  GRINDSTONES  USED  BY  CARPENTERS,  SMITHS,  and  many  others,  and 
which  stones  vary  from  about  two  to  four  feet  in  diameter,  are  often 
mounted  very  nearly  the  same  as  the  last,  so  as  to  be  worked  with  a  winch- 
handle,  which  is  then  however  turned  by  an  assistant,  but  the  frames  for 
these  larger  stones  are  continued  to  the  ground,  or  are  sometimes  let  into 
the  ground,  and  between  the  four  legs  of  the  frame  is  placed  the  wate,r 
trough. 

In  these  cases,  there  is  no  objection  to  the  stone  dipping  a  little  way  into 
the  water  whilst  it  revolves,  as  the  surface  velocity  of  the  stone  can  be 
scarcely  so  great  as  to  cause  the  water  to  be  thrown  off  by  the  centrifugal 
motion  ;  but  the  stone  should  not  be  allowed  to  remain  immersed  at  one 
particular  part,  or  it  will  be  there  softened  and  become  more  disposed  to  wear 
irregularly  ;  the  trough  is  consequently  often  suspended  on  a  hinge  or  joint 
at  the  one  extremity,  and  hung  up  by  a  chain  at  the  other,  so  that  it  may  be 
occasionally  raised  for  moistening  the  stone. 

6. — GRINDSTONES  MOVED  WITH  TREADLES. — For  stones  from  about  20  to  40 
inches  diameter,  this  method  is  highly  to  be  commended,  as  the  stone  whilst 
in  rotation,  then  supplies  enough  momentum  to  act  as  a  fly-wheel,  and  in 
such  cases  it  is  only  needful  that  some  part  of  the  iron  axis  for  the  stone 
should  be  formed  as  a  crank  of  three  or  four  inches  radius,  from  which  a 
connecting  rod,  or  crank  hook  should  descend  to  the  treadle,  jointed  to  the 
two  back  feet  of  the  framework,  nearly  as  in  a  turning  lathe.  A  higher 
velocity  may  be  thus  given  to  the  grindstone  than  with  a  winch-handle,  and 
the  workman  does  not  require  an  assistant  to  put  the  stone  in  motion  as 
when  a  winch-handle  is  used.  The  employment  of  the  treadle,  is  even  now 
far  from  being  so  general  as  it  deserves  to  be,  notwithstanding  that  it  was 
known  and  published  so  long  as  three  centuries  back. 

• 


1105  DESCRIPTIVE    CATALOGUE    OF    APPARATUS,    MATERIALS, 

7. — GRINDING  LATHES,  OR  SMALL  GRINDSTONES  DRIVEN  BY  FOOTWHEELS  AND 
TREADLES. — Stones  not  exceeding  a  foot  to  a  foot  and  a  half  diameter,  do 
not  present  sufficient  momentum  to  admit  of  their  being  driven  as  in  the  last 
example,  unless  a  foot  wheel  of  moderate  weight  is  added  to  the  lower  part 
of  the  frame,  the  upper  part  of  which  then  carries  the  grindstone  spindle 
fitted  with  a  pulley,  so  that  a  leather  strap  or  a  catgut  band  may  communi- 
cate the  motion  of  the  foot- wheel  to  the  spindle,  in  a  manner  analogous  to 
that  employed  in  foot-lathes  ;  whence  this  arrangement  has  been  called  the 
GRINDING  LATHE.  The  same  frame  or  lathe  is  commonly  fitted  with  buff 
and  brush  wheels,  and  is  then  much  used  by  cutlers  for  many  parts  of  their 
works,  that  require  but  secondary  care  ;  this  apparatus  is  also  used  by  many 
of  the  workers  in  horn,  tortoiseshell,  ivory  and  other  materials  ;  but  cutlers 
always  polish  the  blades  and  superior  parts  of  cutlery,  upon  the  apparatus 
next  to  be  described. 

8. — CUTLERS'  GRINDSTONE  DRIVEN  BY  THE  FLY  WHEEL. — Cutlers'  grindstones 
range  from  about  6  to  24  inches  diameter,  and  are  fixed  upon  square  iron 
spindles  from  12  to  30  inches  long,  terminating  in  steel  pointed  centers  ;  the 
stone  is  wedged  fast  near  the  right  hand  extremity  of  the  spindle,  and  near 
the  left  is  fixed  the  pulley  for  a  leather  strap  which  usually  measures  from 
1  to  2  inches  wide.  The  strap  commonly  proceeds  from  a  hand-wheel  of 
about  5  or  6  feet  diameter,  turned  by  a  labourer  who  is  situated  at  the  back 
of  the  grinder,  and  the  entire  arrangement,  from  the  length  of  space  occupied 
is  familiarly  termed  the  long  wheel,  but  in  large  establishments,  the  stones  are 
generally  driven  by  steam  or  other  power. 

The  framework  for  supporting  the  grindstone  spindle,  usually  consists  of 
two  long  pieces  or  sleepers  that  lie  on  the  ground  and  are  united  at  their 
extremities,  they  have  near  the  one  end  two  perpendicular  posts  or  standards, 
at  the  upper  parts  of  which  are  placed  the  hollow  centers  for  the  spindle 
to  run  in ;  lignum  vitse  is  the  material  preferred  for  the  centers,  horn  is 
sometimes  used,  and  in  a  few  cases  screws  with  steel  centers  are 
employed.  The  center  block  on  the  left  hand  for  the  centers  near  the 
leather  strap,  is  usually  pierced  with  three  or  four  holes  on  a  horizontal  line, 
for  the  convenience  of  making  the  strap  more  or  less  tight,  and  also  for  adapt- 
ing it  to  pulleys  differing  somewhat  in  diameter,  without  shifting  the  wheel. 
Sometimes  the  post  for  the  center  on  the  right  hand,  is  fitted  between  two 
transverse  pieces  or  bearers,  and  secured  by  a  wedge,  like  the  popit  heads 
of  very  common  turning  lathes  in  order  to  serve  for  spindles  of  various 
lengths ;  because  the  same  frame-work  is  commonly  used  by  the  cutler  not 
only  for  grindstones,  but  also  various  laps,  buffs  and  glaze  wheels. 

The  Sheffield  grinders  generally  employ  ash  for  the  center  blocks  and 
wedges  for  grindstone  spindles,  and  they  mostly  run  all  their  stones  and 
glazers  in  one  set  of  holes,  and  adjust  the  length  of  the  straps  for  various 
sized  pulleys  by  using  short  pieces  of  strap  of  different  lengths,  which  they 
apply  by  means  of  round  buckles. 

Between  the  standards  and  below  the  stone  lies  a  long  narrow  water 
trough  of  wood  lined  with  lead  or  of  cast  iron,  sometimes  called  the  "  dog 


AND    PROCESSES    FOR    GRINDING    AND    POLISHING.  1106 

pan"  but  which  should  never  contain  enough  water  to  reach  the  stone,  as 
the  centrifugal  motion  would  splash  the  water  about  in  an  inconvenient 
degree  ;  the  water  is  therefore  at  intervals  thrown  on  from  a  pail  with  the 
hand,  or  is  allowed  to  flow  from  a  thread-like  jet  on  the  side  of  the  stone 
very  near  its  periphery.  The  workman  is  seated  astride  a  board  called  the 
horse,  which  rests  behind  on  the  bearers  or  sleepers  of  the  frame,  and  in  front 
is  propped  up  by  a  transverse  bar  of  wood,  which  is  shifted  to  or  from  the 
stone,  to  adjust  the  front  end  of  the  horse  to  a  convenient  height,  dependent 
on  the  diameter  of  the  grind-stone. 

The  edge  of  the  horse  near  the  stone  is  commonly  shod  with  iron,  that  it 
may  be  used  for  supporting  the  turning  tool  employed  in  turning  up  the 
grindstone,  and  the  horse  has  mostly  also  a  piece  of  leather  or  sacking  or  a 
sloping  board  to  keep  off  the  wet  thrown  up  by  the  centrifugal  motion.  The 
framework  is  sometimes  furnished  with  a  splash-board,  which  is  placed 
almost  perpendicularly  on  the  other  end  of  the  trough,  and  projects  above 
the  top  of  the  stone,  so  as  to  catch  most  of  the  water  that  flies  off  and 
reconduct  it  to  the  trough  ;  but  the  splash  board  is  not  always  added. 

9. — THE  POSITION  OF  THE  GRINDER  WHEN  AT  WORK  is  highly  favourable,  he  is 
seated  before  and  rather  above  the  stone,  with  his  feet  resting  upon  the 
ground  or  other  firm  support,  and  in  the  act  of  grinding  and  polishing  deli- 
cate works,  they  are  held  by  both  extremities  in  the  two  hands,  whilst  the 
elbows  rest  upon  the  knees,  so  that  the  grinder  can  thus  keep  his  person  very 
steady,  and  is  enabled  to  feel  with  great  delicacy  and  exactness  the  position 
of  the  work  upon  the  stones  or  polishers.  But  in  polishing  the  handles, 
springs,  middle  parts  of  pocket  knives,  and  other  small  pieces  the  cutler 
frequently  employs  the  grinding  lathe  just  described  in  article  7. 

10.— LARGE  GRINDSTONES  FOR  HEAVY  EDGE  TOOLS,  SAWS,  GUN  BARRELS  &c. 
Manufacturers  in  these  branches  use  much  heavier  grindstones  than  cutlers, 
and  mount  them  somewhat  differently.  Stones  larger  than  3  feet  diameter 
and  4  or  5  inches  thick,  and  those  extending  to  the  dimensions  of  8  or  10  feet 
diameter,  and  12  to  16  inches  thick,  are  commonly  wedged  upon  square 
spindles  having  cylindrical  necks,  that  run  on  bearings  either  of  hardwood 
or  metal,  and  the  pulley  is  generally  placed  at  the  extremity  of  the  spindle 
and  outside  the  one  bearing,  so  that  it  may  be  changed  agreeably  to  the 
decreasing  diameter  of  the  stone  without  the  trouble  of  lifting  the  stone  from 
its  bearings,  which  is  not  commonly  done  until  it  is  worn  too  small  for  its 
particular  use.  A  deep  groove  is  then  turned  in  the  periphery  of  the  stone, 
and  which,  after  removal  from  the  spindle,  is  split  in  two  by  chisels  and  iron 
wedges  to  serve  for  smaller  works. 

The  arrangements  of  the  trough,  horse  and  splash-board,  for  large  grind- 
stones differ  principally  in  size  alone  from  the  preceding  ;  frequently  how- 
ever the  axis  of  the  stone  is  level  with  the  ground,  and  the  bearings  are 
fixed  on  two  sleepers,  between  which  the  earth  is  simply  excavated  to  form 
the  trough,  as  the  grinders'  tools  are  generally  of  the  most  simple  and 
inexpensive  kind. 


1107        DESCRIPTIVE    CATALOGUE    OF    APPARATUS,    MATERIALS, 

1 1 . — LARGE  STONES  ARE  ALWAYS  DRIVEN  BY  POWER,  a  drum  of  three  to  five  feet 
diameter  commonly  extends  across  the  grinder's  shop,  and  the  stones  are 
arranged  in  a  line  on  each  side  of  the  same.  The  surface  velocity  of  the 
drum  is  commonly  about  200  feet  in  a  minute,  and  the  diameter  of  the 
pulley  being  about  one  third  that  of  the  stone,  the  surface  velocity  of  the 
latter  is  from  about  500  to  600  feet  a  minute.  This  speed  gives  rise  with 
large  stones,  to  so  much  momentum  as  to  endanger  their  being  split,  if  there 
should  be  the  smallest  flaw  in  the  stone,  or  that  from  neglect  it  acquires  a 
heavy  side,  from  being  allowed  to  wear  out  of  the  true  concentric  figure. 
The  centrifugal  force  then  sometimes  breaks  the  stone,  and  drives  the  huge 
fragments  with  frightful  violence  through  the  roof  or  walls  of  the  building, 
to  the  occasional  destruction  of  human  life. 

12. — FLANGES  AND  RINGS  TO  PREVENT  STONES  FROM  BREAKING.  The  liability 
of  grindstones  to  be  broken  by  excessive  centrifugal  force,  is  materially 
lessened  if  not  altogether  averted,  when  four  or  six  holes  are  made  through 
the  stone,  and  iron  plates  or  rings  covering  about  one-third  to  one-half  of 
the  diameter  are  bolted  on  each  side,  sacking,  felt,  pitch  or  some  soft  mate- 
rials being  interposed,  so  that  the  stone  and  two  side  plates  when  bolted 
together,  may  form  a  compact  solid  mass  ;  Flanges  are  also  used  as  well  as 
rings,  but  neither  of  them  so  generally  as  they  ought  to  be,  especially  when 
from  cupidity  it  is  attempted  to  drive  the  stone  as  fast  it  will  bear  with  hoped 
for  safety,  hi  order  to  hurry  through  as  much  work  as  possible. 

In  the  new  and  unprotected  stone,  there  is  considerable  body  of  the  mate- 
rial or  length  of  radius  to  withstand  fracture,  but  when  the  stone  is  reduced 
to  half  its  primary  diameter,  and  its  axial  speed  is  doubled  to  maintain  its 
original  surface  velocity,  the  risk  is  much  increased,  because  there  is  then  so 
much  less  bulk  in  the  stone  to  resist  accidental  fracture. 

13. — ENGINEERS'  TOOL  GRINDSTONES  or  those  employed  for  keeping  in  order 
their  working  tools  ;  vary  from  two  to  five  feet  diameter,  and  four  to  eight 
inches  thick,  and  as  may  be  supposed,  the  structure  of  the  framing  is 
usually  in  metal,  and  much  more  engineer-like  than  the  last.  For  instance, 
the  trough  is  made  either  entirely  of  cast  iron,  or  with  cast  iron  sides 
united  with  a  wide  strip  of  boiler  plate  rivetted  to  each.  The  trough  has 
usually  feet  to  support  the  axis  at  two  to  two  and  a  half  feet  from  the 
ground,  to  suit  the  erect  position  of  the  workman,  who  holds  the  tool 
securely  on  a  horizontal  iron  bar  that  is  fixed  near  the  stone,  and  at  a  con- 
venient height  by  means  of  pedestals  secured  to  the  frame,  this  arrange- 
ment gives  the  choice  of  position  in  the  rest  or  bar.  The  axis  is  cylindrical 
throughout,  and  the  stone  is  fixed  on  its  central  part,  as  will  be  explained  : 
the  spindle  lies  hi  two  plummer  blocks  or  brasses,  which  are  fixed  on  the 
edges  of  the  trough,  and  one  end  of  the  spindle  overhangs  the  same  to 
receive  the  strap  pulley,  by  which  the  stone  is  driven  from  the  main  shaft 
running  through  the  building.  There  is  likewise  provision  for  changing  the 
diameter  of  the  pulley  on  the  main  shaft  or  on  the  spindle,  to  increase  the 
velocity  of  the  stone  as  it  becomes  reduced  in  diameter  :  but  unlike  the 


AND    PROCESSES    FOR    GRINDING    AND    POLISHING.  1108 

generality  of  machines  in  the  engineers'  shops,  the  grindstone  does  not 
require  fast  and  loose  pulleys  to  connect  or  disconnect  it  with  the  power,  as 
from  its  frequent  use  it  is  kept  continually  running  when  the  engine  is  at 
work. 

Engineers  mostly  fix  the  stone  between  cast-iron  flanges  or  plates,  the 
one  keyed  on  the  spindle  against  a  shoulder,  the  other  forced  up  by  a 
screwed  nut  or  key  passing  through  a  diametrical  mortise  in  the  spindle. 
Mr.  Roberts  of  Manchester  prefers  the  latter  mode,  and  in  hanging  the 
grindstone  he  fits  a  square  piece  of  wood  into  the  eye  of  the  stone,  then  bores 
it  to  fit  the  spindle,  and  afterwards  having  smoothed  the  central  parts  of 
the  sides  of  the  stone,  he  inserts  two  disks  of  soft  pine  wood  between  the 
cast-iron  flanges  and  the  stone, — the  wood  adapts  itself  to  the  trifling  irre- 
gularities of  both  parts,  and  serves  as  a  somewhat  elastic  cushion  to  ensure 
contact,  and  consequently  a  firmer  grasp  on  the  stone,  to  the  extent  of 
about  one-fourth  of  its  diameter,  to  which  the  flanges  extend  ; — by  these  pre- 
cautions accidents  rarely  occur.  Engineers  sometimes  use  stones  of  the 
before-mentioned  diameter  of  8  or  10  feet  for  brightening  the  coarser  parts 
of  machinery,  and  such  large  stones  are  mounted  nearly  the  same  as  those 
just  described,  but  nearer  to  the  ground. 

14. — TURNING  UP  GRINDSTONES.— As  soon  as  the  stone  is  wedged  truly  on  its 
axis,  it  is  turned  on  the  cylindrical  edge  or  face,  and  part  way  down  each 
side.  This  is  done  with  a  rod  of  iron  or  steel  drawn  down  at  the  end  to 
about  -j^ths  to  f  ths  of  an  inch  square.  The  tool  is  not  held  radially  but 
pointed  downwards,  at  an  angle  of  about  20  degrees,  and  is  continually 
rolled  over  and  over  to  present  a  new  angle,  which  in  its  turn  is  rapidly 
worn  away.  The  process  is  nevertheless  much  quicker  than  might  be  sup- 
posed. 

In  turning  small  grindstones  driven  by  the  long  wheel,  the  stone  is  moved 
the  reverse  way,  and  more  slowly  than  in  grinding,  so  that  the  horse  may 
be  used  for  supporting  the  turning  tool.  In  turning  large  grindstones  driven 
by  power,  in  which  case  the  motion  cannot  be  so  readily  reversed  nor  slack- 
ened, the  workman  goes  to  the  back  of  the  stone  and  supports  the  tool  upon 
a  wooden  or  iron  bar  placed  across  the  water  trough,  and  employs  a  larger 
pulley  than  for  grinding.  Sometimes  a  cross  strap  is  allowed  to  run  upon 
the  edge  of  the  stone  itself,  to  reverse  and  reduce  the  speed  of  the  stone 
when  it  is  turned  after  having  been  mounted. 

Large  stones  are  seldom  turned  up,  except  when  they  are  first  set  to 
work,  but  they  are  retained  of  a  cylindrical  or  slightly  convex  figure,  almost 
exclusively  by  the  following  process  : — 

15. — HACKING  GRINDSTONES. — At  interval^  during  the  time  a  large  grindstone  is 
in  regular  work,  the  strap  is  flung  off  and  the  stone  is  retarded  by  still 
applying  to  its  surface  the  article  to  be  ground  ;  but  before  the  stone  comes 
to  rest,  the  high  places  are  marked  at  six  or  more  parts  of  its  width,  by 
holding  a  piece  of  chalk  or  charcoal  steadily  upon  the  horse,  and  gradually 
approaching  it  so  as  to  mark  the  more  prominent  parts.  When  the  stone 

G2 


1109        DESCRIPTIVE    CATALOGUE    OF    APPARATUS,    MATERIALS, 

has  stopped,  the  grinder  hacks  or  notches  the  high  places  denoted  by  the 
marks,  by  means  of  a  tool  called  a  "  hack  hammer"  which  is  like  a  small 
adze  of  2  or  3  Ibs.  weight,  but  longer  and  more  curved  in  the  blade,  and 
with  a  very  short  handle.  The  grinder  cuts  with  the  hack  hammer  shallow 
oblique  furrows  about  one  inch  asunder  and  crossing  each  other,  producing 
a  chequered  surface. 

When  the  stone  is  again  used,  the  greatest  wear  occurs  at  these  roughened 
places,  and  by  a  continual  recurrence  to  the  dressing  the  circularity  of  the 
stone  is  sufficiently  well  preserved,  and  with  but  little  interruption  to  the 
work.  It  is  very  impolitic  to  defer  the  dressing  too  long,  for  fear  of  giving 
the  stone  a  heavy  side,  and  risking  its  safety. 

16. — STRAGGLING  OB  RAGGING. — This  process  is  principally  adopted  on  fine  and 
smooth  grindstones  into  the  surfaces  of  which  particles  of  iron  or  steel  have 
become  embedded,  and  which  greatly  impede  the  action  of  the  stone.  In 
straggling,  or  ragging,  the  stone  is  kept  running  as  usual  whilst  a  piece  of  soft 
iron  about  a  quarter  or  half  an  inch  square,  held  upon  the  horse  like  the 
turning  tool,  is  wriggled  against  the  edge  of  the  stone  by  a  motion  of  the 
wrist,  as  in  using  a  brad-awl,  the  iron  is  applied  all  over  the  surface,  and 
lastly  the  edge  of  the  bar  is  wriggled  obliquely  upon  the  top  of  the  stone. 
This  process  also  assists  in  correcting  small  inequalities  in  the  figure  of 
the  stone. 

17. — TURNING  AND  ROVING  SMOOTH  GRINDSTONES. — A  different  and  perhaps  more 
general  mode  of  keeping  the  stone  in  order,  especially  when  it  is  driven  by 
the  hand  wheel,  is  followed  by  other  workmen. 

The  motion  of  the  stone  is  reversed,  and  the  edge  is  turned  with  a  bent 
tool,  usually  made  out  of  an  old  file,  by  forging  the  end  taper  and  to  a  thin 
wide  chisel  edge,  and  about  one  inch  of  the  tool  is  then  turned  up  nearly  at 
right  angles  to  the  stem  of  the  file.  This  tool  is  used  as  a  hooked  turning  tool 
upon  the  horse,  and  it  scrapes  the  surface  tolerably  true  and  smooth,  and 
afterwards  whilst  the  stone  is  at  work  its  edge  is  cleared  with  the  roving 
plate,  a  piece  of  either  iron  or  steel  plate  just  like  a  joiner's  scraper,  held 
upon  the  top  of  the  stone  not  quite  perpendicularly  but  meeting  the  stone  at 
a  small  angle. 

From  its  unstable  position  the  roving  plate  chatters  and  jumps,  and 
appears  to  fill  the  stone  with  minute  furrows  from  dislodging  some  of  the 
particles  from  its  gritty  surface.  This  mode  also  gives  the  stone  a  tooth, 
and  as  well  as  the  last  method  serves  to  clear  the  stone  from  the  thick  dirty 
water  or  slush  that  otherwise  fills  its  grain  and  considerably  retards  its 
action,  frequently  also  the  grinder  throws  a  small  handful  of  water  on  the 
stone,  and  applies  his  open  hand  very  gently  upon  the  same,  in  order  to  wash 
off  the  loose  muddy  coating  it  acquires  whilst  in  use. 

1 8. — GENERAL  REMARKS  ON  USING  GRINDSTONES. — In  order  to  avoid  the  waste- 
ful destruction  of  the  stones  they  should  be  exposed  to  as  equal  circumstances 
as  possible  ;  thus  they  should  in  the  first  instance  be  selected  free  from  hard 
veins  that  impede,  or  flaws  that  accelerate  the  wear  at  the  respective  parts. 


AND    PROCESSES    FOR    GRINDING    AND    POLISHING.  1110 

The  object  ground  should  be  continually  traversed  backwards  and  forwards 
to  use  the  stone  alike  all  over,  the  stones  should  not  be  allowed  to  remain 
long  out  of  condition,  as  they  get  rapidly  worse,  neither  should  they  ever 
remain  partially  immersed  in  the  water  in  the  trough,  which  would  soften 
those  parts  and  expose  them  to  more  rapid  wear,  than  the  remainder. 

In  almost  every  case  the  grindstone  is  made  to  revolve  away  from  the 
workman,  so  that  should  the  work  slip  from  his  grasp  it  may  be  carried  away 
from  his  person  and  not  against  him.  But  this  direction  of  motion  leaves  a 
wiry  film  on  tools  with  thin  cutting  edges,  and  which  the  regular  grinder 
occasionally  avoids,  by  holding  the  tool  lack-handed)  or  with  the  edge 
towards  his  person.  Many  of  the  tools  used  in  turning  metal  do  not  require 
to  be  sharpened  on  the  oilstone,  and  to  avoid  the  wiry  film,  such  tools  are 
usually  ground  with  the  stone  running  towards  the  workman. 

The  Bilston  grindstone  has  the  preference  for  small  tools  from  the  compa- 
rative smoothness  of  its  grain,  and  occasionally,  a  coarse  and  a  fine  stone  are 
fixed  on  the  same  spindle  ;  and  when  the  shop  grindstone  is  driven  by 
power,  the  workman  goes  to  the  front  or  back  of  the  stone  accordingly  as 
the  motion  is  best  suited  to  his  immediate  want. 

19.— GENERAL  REMARKS  ON  GRINDING  VARIOUS  KINDS  OP  TOOLS. — The  general 
position  of  the  grinder  described  under  article  9,  serves  for  grinding  all 
ordinary  tools,  such  as  chisels,  axes,  and  many  others  of  ordinary  kinds, 
which  are  simply  held  to  the  stone  by  the  hands,  and  receive  the  pressure 
of  the  arms  and  upper  part  of  the  person. 
20. — Massive  works,  such  as  anvils,  are  suspended  loosely  by  a  chain,  the  man 

has  then  only  to  guide  them,  and  their  own  weight  supplies  the  pressure. 
21. — Large  heavy  plates,  such  as  the  bright  cast-iron  fronts  of  stoves,  are 
allowed  to  rest  in  an  oblique  position,  jointly  upon  the  surface  of  the  horse 
and  the  stone,  the  grinder  slides  them  about,  to  expose  all  parts  of  the  sur- 
face to  equal  action,  and  often  bears  on  them  with  his  knees  to  increase  the 
pressure. 

22. — Saws  are  too  thin  and  elastic  to  be  thus  treated,  and  such  flexible 
objects  are  applied  on  a  flat  board  to  give  them  support,  the  man  leans  upon 
the  board  with  his  whole  weight  and  moves  them  up  and  down  at  an  inclina- 
tion of  about  45  degrees  to  grind  each  part  successively  and  equally. 
23. — The  llades  of  table  Tcnives  are  before  being  handled  ground  on  the  side 
of  a  stick,  about  2^  by  1^  inches  and  2  feet  long  with  a  staple  under  which 
the  shank  of  the  blade  is  placed,  the  stick  is  rounded  at  the  ends  to  serve  for 
the  two  hands,  and  the  workman  sometimes  applies  also  his  knees  to  the 
central  part,  and  the  effect  of  the  stone  is  then  very  rapidly  felt  on  the 
blade. 

24. — Small  works  that  are  ground  lengthways,  are  sometimes  nipped  between 
the  horse  and  the  stone,  an  enormous  pressure  may  be  then  given  much  less 
laboriously  than  by  the  arms,  this  is  often  done  in  grinding  the  surface  of 
files  preparatory  to  their  being  cut  with  teeth,  and  in  stripping  the  teeth 
from  old  ones,  prior  to  re-cutting  them  ;  but  this  practice  throws  a  great 


1111        DESCRIPTIVE    CATALOGUE   OF    APPARATUS,    MATERIALS, 


pressure  on  the  stone,  sometimes  enough  to  check  the  speed  of  the  steam 
engine. 

25. — Small  works  are  in  many  cases  difficult  to  le  held  unassistedly,  because  of  the 
risk  of  grinding  through  the  skin  of  the  fingers,  or  of  burning  them  from  the 
heat  of  the  work,  a  small  pointed  stick  is  frequently  used  to  press  the  work 
on  the  stone,  and  in  some  cases  a  small  square  piece  of  thick  leather  or  felt, 
called  a  patchy  is  similarly  employed.  Sometimes  also  small  tools  are  tem- 
porarily fixed  by  their  tangs  in  a  wooden  handle  to  facilitate  their  presenta- 
tion to  the  stone  ;  the  handle  is  called  a  "  haftpipe  "  and  is  commonly  a  short 
piece  of  hazel  rod.  But  the  more  usual  course  at  Sheffield  is  to  employ  a 
pair  of  tongs  or  pliers,  the  reins  of  which  do  not  cross  as  pliers  and  scissors 
generally,  but  consist  simply  of  two  rods  of  iron  retained  by  a  link  across 
their  middle.  The  work  is  fixed  by  being  inserted  between  the  rods  at  the 
one  end,  and  a  wooden  wedge  driven  in  between  the  opposite  extremities, 
binds  the  whole  together  very  securely.  The  sliding  tongs,  fig.  861,  page 
862,  Vol.  II.,  are  also  used  occasionally. 

26. — ADAPTATION  OF  GRINDSTONES  TO  THE  FORMS  OF  WORKS. — Convex  works  may 
of  course  be  ground  upon  the  cylindrical  edge  of  the  grindstone,  as  by  rolling 
the  work  about,  every  part  of  the  same  may  be  brought  into  contact  with  the 
stone,  in  the  same  manner  that  round  or  convex  works  may  be  filed  with  a 
flat  file  ;  but  in  grinding  concave  works,  it  is  of  course  needful  that  the  stone 
if  not  altogether  a  counterpart  of  the  work,  should  be  sufficiently  modified  in 
form  to  penetrate  to  the  bottom  of  the  hollow. 

Thus  in  grinding  a  pruning  bill,  the  hook  of  which  is  of  small  radius,  it  is 
indispensable  the  one  edge  of  the  stone  should  be  rounded  to  the  fourth  of  a 
circle  ;  in  grinding  that  part  of  a  table  knife  where  the  blade  is  united  to  the 
shank,  a  similar  curvature  in  the  stone  is  also  required.  In  grinding  hollow 
or  fluted  works  such  as  the  concave  parts  of  gouges,  it  is  necessary  to  turn 
the  grindstone  to  the  exact  counterpart  form,  or  into  beads  of  different  width 
and  sweeps,  and  various  other  examples  might  be  quoted. 

In  order  to  reach  within  that  keen  edge  in  the  blade  of  a  penknife  which 
unites  the  square  shank  for  the  joint  to  the  remainder  of  the  blade,  (which 
angle  is  technically  called  the  chorl,)  the  edge  of  the  stone  is  kept  remark- 
ably keen  and  sharp,  this  is  assisted  by  waxing  the  side  of  the  dry  grind- 
stone close  to  the  edge,  and  which  tends  to  prevent  the  same  from  crumbling 
away,  and  also  prevents  the  stone  cutting  into  the  shoulders  of  the  blade. 

27. — WET  AND  DRY  STONES. — Grindstones  are  almost  always  used  with  water,  as 
in  the  humid  state  they  cut  more  quickly,  because  the  wet  prevents  the 
grain  of  the  stone  being  choaked  with  particles  of  metal,  but  when  the  stone 
is  used  dry,  although  it  cuts  somewhat  more  slowly,  it  leaves  a  smoother 
grain  upon  the  work,  and  on  which  account  the  dry  stone  is  always  resorted 
to  by  fork-grinders  and  needle  pointers. 

28. — The  dry  stone  is  somewhat  used  also  by  most  grinders,  but  only  for  a  small 
part  of  their  work,  as  when  vigorously  applied  it  gives  rise  to  so  much 
friction  ;  that  it  frequently  heats  the  work  to  a  blue,  or  almost  to  a  red-heat, 


AND    PROCESSES    FOR    GRINDING    AND    POLISHING.  1112 

and  would  destroy  the  temper  of  the  tools,  its  use  is  therefore  nearly 
restricted  to  the  roughing-out  of  tools,  before  they  are  hardened,  an  opera- 
tion called  "  scorching  "  :  at  this  early  stage  of  the  manufacture  of  tools  they 
receive  no  injury  from  the  great  heat  sometimes  thus  given  them. 

29. — Hardened  and  tempered  blades  that  have  been  ground  on  the  wet  stone,  are 
often  smoothed  on  a  dry  Bilston  stone,  in  order  to  leave  less  work  to  be 
accomplished  in  the  next  stage  of  manufacture,  by  the  metal  lap  with  fine 
emery  ;  but  the  judicious  cutler  then  applies  the  dry  stone  so  moderately  as 
not  to  reduce  the  temper  of  the  blades,  but  only  to  smooth  them. 

30. — DANGER  OF  USING  DRY  STONES. — A  still  worse  and  more  fatal  mischief  than 
spoiling  the  work  attends  the  continual  practice  of  dry  grinding,  as  the  fine 
particles  of  stone  and  steel  that  are  given  off,  raise  clouds  of  dust  which  are 
inhaled  by  the  workmen,  and  so  commonly  does  this  contaminated  atmo- 
sphere induce  pulmonary  complaints,  that  it  is  considered  rare  for  a  needle 
or  fork  grinder  to  live  beyond  the  age  of  twenty-five  or  thirty,  at  which 
period  they  generally  become  afflicted  with  asthma  and  premature  decay. 

31. — To  avert  this  calamity  Mr.  Abraham  of  Sheffield  invented  magnetic  guards 
which  were  placed  close  to  the  grindstone,  and  sometimes  also  around  the 
mouth  and  nostrils  of  the  individual.  (See  Trans.  Soc.  of  Arts,  vol.  40,  plate 
XXIII).  The  magnet  attracted  the  particles  of  steel  and  together  with  them 
drew  the  greater  part  of  the  stone  dust,  but  the  men  were  too  heedless  to 
avail  themselves  of  this  philanthropic  invention,  notwithstanding  its  com- 
plete success. 

32. — The  only  contrivance  now  employed  is  also  due  to  Mr.  Abraham,  the  stone 
is  enclosed  in  a  wooden  case  that  only  exposes  a  part  of  its  edge,  and  from 
the  box  a  horizontal  tube  also  of  wood,  proceeds  as  a  tangent  from  the  upper 
surface  of  the  stone  to  the  external  atmosphere.  The  current  of  air  gene- 
rated by  the  motion  of  the  stone  makes  its  escape  through  the  tube,  and 
carries  with  it  nearly  the  whole  of  the  dust  arising  from  the  process  ;  some- 
times the  tube  alone  is  retained. 

But  even  this  contrivance,  (which  may  be  viewed  as  comparable  with  the 
revolving  fan  now  used  in  blowing  furnaces,)  although  so  much  less  elaborate 
than  the  magnetic  guards,  yet  nearly  as  effective,  is  also  for  the  most  part 
neglected,  owing  to  the  unpardonable  heedlessness  of  the  workmen  them- 
selves. 

Mr.  W.  Lund  invented  an  apparatus  almost  identical  with  Clark's  revolv- 
ing blower  with  a  small  fan,  it  was  driven  by  a  short  band  from  the 
stone,  and  was  described^  in  the  Mechanic's  Magazine  under  the  signature 
"  Gulielmus,"  this  also  merely  obtained  a  very  limited  use. 


SECTION  B. — WHEELS  OF  FACTITIOUS  STONE,  OR  COMPOSITION  WHEELS. 
33. — OF  COMPOSITION  WHEELS  the  corundum  wheels  deserve  the  first  notice, 
they  consist  of  particles  of  corundum  cemented  into  a  mass  by  means  of 
shell  lac,  and  which  composition  variously  prepared  is  nearly  the  universal 


1113         DESCRIPTIVE    CATALOGUE    OF    APPARATUS,    MATERIALS, 

grindstone  and  polisher  of  the  East  Indies.  The  reader  is  referred  for  the 
details  of  their  preparation  to  the  article  CORUNDUM  in  this  Catalogue. 

34. — BARCLAY'S  ARTIFICIAL  EMERY  STONES. — The  manufacture  of  these  very 
useful  grinding  and  polishing  wheels,  is  fully  described  under  the  head 
EMERY  article  11  :  in  most  respects  they  are  superior  to  the  corundum 
wheels  of  the  Asiatics  described  under  the  head  CORUNDUM.  They  may  each 
be  made  of  various  degrees  of  coarseness  and  rapidity  of  cut  ;  when  pro- 
perly compounded  their  texture  is  very  uniform  and  free  from  the  hard 
veins  and  flaws  that  sometime  occur  in  grindstones. 

35. — OPTICIANS  sometimes  employ  fine  crocus  made  into  a  solid  body  with  wax, 
and  moulded  or  turned  into  form  (see  the  article  on  LENSES  and  SPECULA) 
in  Chap.  XXXIII.  Sect.  4.  The  wax  polisher  is  generally  used  with 
water,  which  greatly  prevents  the  destruction  of  its  surface  and  also  assists 
in  carrying  off  those  particles  of  glass  or  metal  which  do  not  become 
embedded  in  the  polisher.  The  introduction  of  this  composition  is  ascribed 
to  Mr.  Varley. 

36. — Crocus,  mixed  with  powdered  chalk  and  melted  glue,  constitute  a  com- 
position employed  by  Mr.  Bass  in  the  formation  of  little  wheels,  employed 
by  him  in  sharpening  the  long  slender  straight  blades  of  his  cork  cutting 
machine.  In  cutting  each  cork  the  knife  sweeps  by  against  a  square  piece 
of  cork,  which,  during  the  time,  makes  one  revolution,  and  the  four  angles 
are  removed  in  one  piece.  The  knife  in  proceeding  to  and  fro,  is  rubbed  on 
its  upper  side  by  three  of  the  crocus  wheels  which  revolve  slowly  against  it 
with  slight  pressure,  and  the  lower  side  of  the  knife  rubs  against  two  or 
three  hard  steel  rings,  which  act  as  burnishers  and  keep  up  the  fine  wiry 
edge  required  in  cutting  cork. 

SECTION  C. — WHEELS  OP  METAL,  OR  METALLIC  LAPS. 

37. — METAL  WHEELS  OR  LAPS,  made  of  nearly  every  metal  and  alloy  in  common 
use,  have  been  more  or  less  employed  in  the  mechanical  arts,  as  vehicles 
for  the  application  of  several  of  the  polishing  powders,  but  of  all  laps, 
notwithstanding  their  variety,  those  of  lead  slightly  alloyed,  and  supplied 
with  powdered  emery,  render  the  most  conspicuous  service.  Generally  the 
plane  or  flat  surface  of  the  lap  is  employed,  at  other  times  the  cylindrical 
edge,  as  by  cutlers,  but  the  portion  actually  used  is  in  either  case  called  the 
face  of  the  lap. 

38. — LAPIDARIES,  MARBLE  WORKERS,  sometimes  also  mechanicians  and  others, 
place  the  spindle  vertically,  so  that  the  lap  revolves  in  a  horizontal  plane, 
and  in  which  case  the  lower  end  of  the  spindle  is  supported  in  a  center  fixed 
to  the  cross  rail  of  the  wood  frame  or  bench,  the  upper  in  a  bracket  or 
overhanging  arm  extending  from  the  platform,  and  beneath  the  latter  is 
placed  the  pulley  by  which  the  spindle  is  driven.  In  some  cases  the  upper 
center  is  dispensed  with,  and  the  spindle  works  in  a  metal  collar  just 
beneath  the  lap — after  the  manner  of  a  lathe,  if  we  conceive  the  mandrel 
to  be  placed  perpendicularly. 


AND    PROCESSES    FOR    GRINDING    AND    POLISHING.  1114 

The  lap  in  all  these  cases  revolves  within  a  shallow  trough,  extended  two 
to  six  inches  above  the  lap,  in  order  to  catch  the  emery  and  water  that  are 
thrown  off.  The  emery  is  usually  applied  dry,  the  lap  having  been  previously 
moistened  with  a  small  brush  dipped  in  water  or  with  a  mop  made  by 
twisting  a  wire  around  a  few  rags,  the  wire  serving  also  as  the  handle,  the 
dry  emery  powder  then  readily  adheres  to  the  lap,  and  less  water  is  required 
than  if  the  emery  and  water  were  previously  mixed.  In  some  cases  the  lap 
is  screwed  upon  the  mandrel  of  an  ordinary  turning  lathe  like  a  chuck,  but 
which  is  hazardous,  lest  the  emery  should  find  its  way  to  the  collar  of  the 
lathe  mandrel. 

39. — CUTLERS'  LAPS  are  fixed  on  spindles  placed  horizontally,  in  fact  in  the 
same  form  that  serves  for  their  grindstone  and  other  apparatus.  Cutler's 
laps  measure  from  about  i  to  20  inches  in  diameter,  the  best  razors  being 
smoothed  on  laps  of  4  to  6  inches  diameter,  and  commoner  razors  on 
those  from  10  to  12  inches,  which  act  the  more  expeditiously  but  leave  a 
thicker  edge. 

40. — DIFFERENCES  OF  CONSTRUCTION  IN  LAPS. — The  lap  is  in  some  cases  a  thin 
disk  of  metal  fixed  by  means  of  a  screwed  nut  against  a  shoulder  on  the 
spindle,  but  it  is  better  with  lead  laps  to  employ  an  iron  plate  cast  full  of 
holes  to  support  the  softer  metal.  The  casting  mould  may  in  this  case  be 
either  an  iron  disk  with  a  central  screw  to  fix  the  iron  center  plate  at  the 
time  of  pouring,  or  the  mould  may  be  made  of  sand  and  in  halves  after  the 
usual  manner  of  the  foundry.  In  either  case  the  iron  plate  should  be  made 
as  hot  as  the  fluid  metal,  which  by  entering  the  holes  becomes  firmly  united 
to  the  iron  especially  if  the  holes  are  largest  on  the  reverse  side  or  that 
away  from  the  lead. 

41. — CUTLERS'  NARROW  CYLINDRICAL  LAPS  are  sometimes  similarly  cast  upon 
the  edges  of  cast-iron  wheels  or  disks,  but  it  is  far  more  usual  to  make  a 
wooden  center  on  account  of  its  lightness.  In  order  that  the  wood  center 
may  not  contract  nor  lose  its  circular  form,  it  is  made  in  four  quarters  or  of 
more  pieces,  with  the  grain  pointing  to  the  center  ;  the  pieces  are  united  by 
two  circular  disks  of  wood  or  metal,  nailed  to  the  sides,  after  this  the  edge 
is  turned  to  the  required  width  and  cylindrical,  with  a  groove  in  the  center 
and  a  chamfer  on  each  edge,  to  retain  the  lead. 

A  better  construction  is  followed  by  Mr.  Lund,  he  makes  his  wheels  of 
common  Honduras  mahogany,  or  rather  a  species  of  cedar,  in  about  thirty- 
two  sections,  and  arranged  in  two  layers  or  disks,  sixteen  in  each,  so  as  to 
break  joint.  No  nails  are  used,  and  although  the  parts  are  only  united  by 
glue  they  are  found  to  endure  the  transitions  from  heat  to  damp  to  which 
they  are  often  exposed.  In  uniting  them  they  are  glued  joint  by  joint,  and 
quickly  arranged  together  upon  a  flat  board,  and  when  nearly  a  half  circle  is 
combined,  a  few  nails  are  driven  round  the  margin  to  allow  the  last  wedge 
or  sector  to  be  driven  in  tight ;  when  two  such  sectors  are  dry  the  last  wedge 
is  fitted  into  the  space  between  them  with  the  trying  plane,  and  driven  in 
tight  to  make  out  the  last  joint,  the  parts  being  restrained  from  slipping 

' 


1115         DESCRIPTIVE    CATALOGUE    OF    APPARATUS,    MATERIALS, 

away  by  the  use  of  a  few  nails  as  before,  lastly  the  two  circles  when  flattened 
are  glued  together  and  compressed  by  several  hand  screws. 

The  mould  for  casting  laps,  is  in  general  an  old  grindstone  in  the  center  of 
which  is  placed  the  wooden  disk,  and  around  the  latter  is  built  up  at  the 
distance  of  1  or  2  inches  a  border  of  soft  clay.  The  metal,  usually  1  part 
tin  and  4  or  5  parts  lead,  (the  lining  of  tea  chests  being  preferred,  on 
account  of  the  tin  with  which  it  is  alloyed  and  soldered,)  is  then  melted  and 
poured  in,  but  the  heat  should  be  barely  such  as  to  scorch  white  paper.  The 
lap  when  cold  is  fixed  on  the  spindle,  and  its  edge  is  turned  true,  the  horse 
being  used  as  the  support  for  the  turning  tool. 

42. THE  CYLINDRICAL  EDGE  OF  THE  LAP,  and  which  alone  the  cutler  employs, 

is  called  the  face,  and  the  dressing  or  coating  of  emery,  which  is  never  used 
by  cutlers  with  water,  is  called  the  head,  terms  applied  in  common  to  his 
other  wheels.  In  order  to  make  the  smooth  metal  retain  the  fine  emery,  it 
is  scored  or  scratched  with  a  pointed  knife,  by  which  two  series  of  slight 
oblique  furrows  are  scored  in  the  face  of  the  lap,  to  produce  a  faintly  but 
coarsely  checkered  surface. 

43. — IN  LAPPING  RAZORS  AND  LARGE  ARTICLES,  fine  emery  and  oil  are  mixed  up 
in  a  cup,  a  small  quantity  is  spread  on  with  the  thumb  whilst  the  lap  is  nearly 
at  rest,  the  emery  is  then  pressed  in  the  lap  with  a  spoiled  razor  blade,  or  a 
short  bar  of  razor  steel,  (that  from  which  the  blades  are  forged,)  whilst  the 
lap  is  in  motion,  and  when  the  lap  is  charged  the  work  is  drawn  steadily 
across  from  end  to  end  and  entirely  off  the  lap,  to  reduce  it  to  an  uniform  surface. 
After  having  preparatively  lapped  about  one  dozen  of  razor  blades  on  both 
sides,  which  is  called  the  first  course,  the  process  is  repeated  with  finer  emery, 
or  else  "  to  fine  the  lap,"  the  head  is  rubbed  off  with  a  piece  of  felt,  or  with 
thick  woollen  cloth,  and  the  surface  of  the  metal  is  rendered  as  fine  as  pos- 
sible, with  a  smooth  piece  of  flint,  or  with  a  steel  blade  ;  and  the  lapping  is 
completed  in  the  last  course  on  the  nearly  naked  lap,  a  stick  of  charcoal 
being  commonly  used  still  more  to  deaden  the  emery  before  the  flint  is 
applied,  and  the  charcoal  moreover  gives  a  black  polish  that  could  not  other- 
wise be  left  from  the  lap. 

44. — IN  LAPPING  PENKNIVES  AND  SMALL  ARTICLES,  it  is  more  usual  to  charge  the 
wheel  whilst  it  is  at  rest,  by  rubbing  on  it  a  lump  of  emery  cake,  made  of 
emery  compounded  with  suet  chopped  fine  and  rendered  down,  and  mixed 
with  a  very  little  wax,  sometimes  the  dressing  is  rubbed  in  with  the  agate  or 
bouldering  stone,  and  as  before  explained,  to  fine  the  lap,  at  the  conclusion 
the  head  is  rubbed  off  and  it  is  smoothed  with  the  agate. 

When  the  lap  is  coarse  and  the  work  is  pressed  heavily  it  produces  a  white 
colour  on  steel,  and  when  the  lap  is  fine  and  the  work  is  pressed  lightly,  and 
gradually  drawn  from  the  one  end  to  the  other  it  gives  a  black  polish— to 
attain  this  end  the  emery  is  worn  down  fine  with  the  work,  and  afterwards 
with  the  bouldering  stone,  and  the  effect  of  the  emery  is  still  more  deadened 
by  putting  a  little  bees' -wax  on  the  face  of  the  lap,  the  smoothness  of  which  is 
tried  with  the  finger  before  applying  the  work. 


AND    PROCESSES    FOR    GRINDING    AND    POLISHING.  1116 

45. — COMPARATIVE  DURABILITY  OF  LAPS. — The  metal  wheels  and  grinding  tools 
are  from  several  reasons  highly  advantageous,  as  in  the  first  place  they 
admit  of  being  fashioned  with  more  exactness,  and  they  longer  retain  that 
exactness  than  the  natural  stones  and  the  compositions  previously  referred 
to.  For  instance  when  grit  stones  are  hi  use,  desintegration  is  constantly 
and  rapidly  going  on,  as  hi  the  course  of  work  the  particles  of  the  stone  are 
rubbed  down  and  torn  out  ;  so  that  the  abrading  surface  is  incessantly  chang- 
ing, by  the  gradual  exposure  of  the  part  of  the  grindstone  previously  beneath. 
Much  care  is  required  to  keep  the  edge  of  the  stone  circular  and  of  the 
precise  form  required. 

With  the  cement  wheels,  this  progressive  change  as  constantly,  although 
more  slowly  occurs,  from  the  abrading  and  structural  materials  being 
mingled. 

46. — ON  THE  ACTION  AND  DURABILITY  OF  LAPS. — Metal  laps  are  under  very 
different  circumstances  from  grindstones  or  cement  wheels,  as  the  metal  con- 
stituting the  lap  has  no  cutting  power  in  itself,  but  only  derives  it  from  the 
particles  of  emery  which  become  embedded  in  its  surface  and  act  as  the 
teeth  of  a  file.  Other  particles  of  the  emery  lie  continually  between  the 
metal  lap  and  the  article  to  be  ground,  and  separate  the  two  ;  these  grains 
have  a  partially  rolling  motion  and,  in  all  probability,  have  a  tendency  to 
grind  both  the  work  and  the  lap  also.  When  the  emery  is  crushed  very 
fine,  or  that  it  is  wasted,  so  that  the  lap  and  work  come  nearly  in  contact, 
the  abrasion  becomes  so  much  reduced  that  fresh  emery  is  generally  thrown 
on  to  restore  the  action,  and  this  again  separates  the  lap  and  work  ;  which 
therefore  rarely  come  into  absolute  contact.  It  must  not  be  supposed,  how- 
ever, that  although  the  metal  is  generally  more  cohesive  than  stone  or  cement, 
that  it  is  not  at  all  worn  away,  as  the  metal  laps  are  likewise  depreciated  in 
form,  but  in  a  much  slower  degree  than  the  cement  wheels  or  natural  stones. 

47. — METALS  EMPLOYED  FOR  LAPS  AND  THEIR  RESPECTIVE  PURPOSES.  —  In  the 
selection  of  the  metals  for  laps,  there  is  much  of  prejudice,  and  speaking 
generally  it  may  be  said  the  softer  the  metals  the  more  readily  do  they  retain 
the  grinding  powders,  but  the  sooner  are  they  worn  out  of  form.  In  the 
following  tabular  view  the  more  usual  metals  for  laps  and  their  purposes 
are  given. 


Opticians,  with  fine  emery  and  water  for  smoothing  lenses  and  specula. 

Cast-iron  is  used  by 

Glass-grinders,  with  coarse  sand  for  roughing  ; 
Opticians,  with  sand  or  emery  for  rough  grinding  ; 
Engineers  and  machinists,  with  emery  and  water  for  general  purposes,  in 

metallic  construction  ; 
Diamond  polishers,  for  polishing  the  facets  of  diamonds  for  jewellery  ;  the  iron 

laps  or  skives  are  charged  with  diamond  powder. 

Copper  is  used  by 
Engineers  and  machinists,  with  emery  and  water  for  general  purposes,  in 


1117        DESCRIPTIVE    CATALOGUE    OF    APPARATUS,    MATERIALS, 

metallic  construction.  Copper  is  considered  to  retain  the  emery  remark- 
ably well  ; 

Lapidaries,  with  flour  emery  for  grinding  small  and  hard  gems,  and  for  cutting 
facets  ; 

Glass  grinders,  with  emery  for  fitting  stoppers  into  bottles  ; 

Glass  engravers,  with  emery  for  their  small  disks  and  tools. 

Lead,  generally  alloyed,  is  used  ~by 
Engineers  and  machinists,  with  emery  and  water,  for  metallic  construction 

generally ; 
Cutlers,  with  emery  and  oil,  for  fine  grinding  or  perfecting  the  forms  of  cutlery 

prior  to  polishing  the  pieces  ; 
Lapidaries,  with  emery,  first  coarse  and  then  fine,  for  grinding  and  smoothing 

most  stones,  except  some  few  of  the  hardest,  which  require  copper  ; 
Lapidaries,  with'rottenstone  and  water,  for  polishing  most  of  the  stones,  except 

a  few  of  the  hardest,  which  require  hard  pewter  or  copper  ; 
Lead,  mixed  with  a  variable  quantity  of  antimony  or  alloy,  like  type  metal,  is 

much  used  by  engineers  and  mechanicians  for  laps. 

Pewter  is  used  by 

Gold  cutters,  for  cutting  and  faceting  gold  and  silver,  to  which  a  most  splen- 
did lustre  is  given  by  means  of  crocus,  which  is  generally  rubbed  into  the 
lap  with  the  burnisher  ; 

Watchmakers,  with  crocus  or  red  stuff  as  above,  for  polishing  some  of  their 
brass  and  steel  works  ; 

Lapidaries,  with  emery  for  fine  grinding,  and  also  with  rottenstone  for  polish- 
ing,— pewter  being  selected  for  those  small  and  hard  stones,  for  which  lead 
is  too  yielding. 

All  these  artizans  select  in  preference  the  metal  of  old  pewter  plates, 
which  consisted  of  pure  tin  with  a  minute  addition  of  copper.  Some  of  the 
modern  pewters  appear  to  be  tin  and  lead  in  nearly  equal  parts,  and  are 
much  the  same  when  used  for  laps,  as  lead  hardened  with  a  little  antimony, 
which  is  much  less  expensive.  See  articles  Pewter,  vol.  i.,  page  284,  and 
LEAD,  page  277  of  the  same  volume. 

Tin  may  be  considered  as  being  applicable  to  all  the  purposes  of  the  genuine  old 
plate  pewter,  which  is  now  difficult  to  be  met  with. 

Zinc,  alloyed  with  tin,  which  is  much  harder  than  tin  or  pewter,  is  said  by  Mr. 
Gill  to  be  employed  by  the  Geneva  jewellers  in  lapping  gold  and  silver 
works. 


SECTION  D. — WHEELS  OF  WOOD,  OB,  GLAZE  WHEELS. 

48. — LAPIDARIES  employ  wooden  wheels  in  smoothing  soft  and  rounded  stones. 
The  wheels  consist  usually  of  beech,  birchwood,  or  mahogany,  cut  out 
plankways,  fixed  on  the  spindle  and  turned  flat.  The  wood  wheels  are  fed 
with  flour  emery  and  water,  as  described  under  the  article  in  this  Catalogue 
on  ALABASTER. 


AND    PROCESSES    FOR    GRINDING    AND    POLISHING.  1118 

49. — GLASS  CUTTERS  employ  the  edges  of  similar  wheels  with  pumice-stone  and 
water  for  smoothing,  and  with  putty  and  water  for  polishing  ;  the  edge  of 
the  wheel  is  turned  flat,  angular  or  circular,  according  to  the  fashion  of 
the  work.  Willow,  poplar  or  alder,  which  are  amongst  the  softest  of  our 
woods,  are  much  used  for  the  glass  cutters'  wheels  :  their  face  wheels,  which 
are  far  less  common,  are  mostly  thick  transverse  sections  of  the  tree,  and 
consequently  the  grain  is  then  upright  at  every  part,  and  both  more  equable 
and  durable. 

50. — CUTLERS  use  wood  wheels  under  the  name  of  glazers  ;  these  should  be  con- 
structed of  two  layers,  each  consisting  of  6,  8  or  more  pieces  with  the  grain 
radial,  so  that  the  periphery  may  be  entirely  formed  of  the  end  grain  of  the 
wood  ;  walnut,  oak,  crab-tree,  birch  and  mahogany  are  severally  used,  but 
the  latter  is  on  the  whole  the  best.  The  cutlers'  wood  or  glaze  wheels  are 
mostly  fed  with  emery  cake,  already  described,  and  which  is  applied  whilst 
the  wheel  slowly  revolves. 

The  edges  of  glazers  are  occasionally  scored  with  a  pointed  knife,  to 
enable  the  emery  cake  to  penetrate,  and  for  fine  work,  they  are  also  boul- 
dered  down  with  a  flint,  or  other  hard  and  smooth  stone,  and  waxed  to 
render  the  edge  smooth,  just  in  the  manner  recently  explained  in  reference 
to  cutlers'  laps.  Sometimes  a  wood  wheel  fed  with  emery  and  oil  is  first 
used,  and  afterwards  a  wood  wheel  with  emery  and  wax. 


SECTION  E. — WHEELS  OF  LEATHER,  OR  BUFF  WHEELS,  GLAZERS  AND 
POLISHERS. 

51. — This  title  includes  three  different  kinds  of  apparatus,  all  of  which  have 
wooden  centers  covered  with  leather,  and  are  thence  sometimes  indiscrimi- 
nately called  buff  wheels,  but  they  are  distinguished  into  three  kinds  as  above 
by  practical  men,  thus : 

First.  Buff  wheels  which  are  covered  with  thick  soft  leather,  sometimes 
half  an  inch  thick,  the  bull  neck  being  commonly  employed.  In  the  metro- 
polis old  regimental  belts  are  sometimes  used  from  economical  motives, 
instead  of  the  new  kinds  of  leather  above  named,  but  this  seems  to  be  a 
questionable  policy,  as  the  belt  leather  is  less  durable,  and  although  it  may 
serve  for  glazers,  it  is  too  thin  for  buff  wheels.  The  coarse  buff,  or  sand 
buff,  is  supplied  with  Trent  sand  and  oil,  the  fine  buff,  with  rottenstone  and 
oil ;  these  are  not  used  for  steel  but  for  softer  metal  such  as  brass,  Britannia 
metal,  &c.,  and  for  horn,  tortoiseshell  and  ivory. 

Secondly.  Glazers  are  wheels  covered  with  harder  leather,  upon  the  face 
of  which  emery  is  attached  by  glue,  they  are  almost  invariably  used  dry,  and 
for  steel.  The  leather  used  for  glazers  and  polishers  in  the  manufacturing 
towns  of  Sheffield  and  Birmingham  is  "beast  hide,"  that  is,  the  same 
leather  which  when  hammered  is  used  for  the  soles  of  shoes,  the  leather  is 
cut  into  strips,  and  used  without  having  been  hammered,  the  thick  and 
thin  parts  being  selected  according  to  circumstances  ;  as  glaze  wheels  require 


1119        DESCRIPTIVE    CATALOGUE    OF    APPARATUS,    MATERIALS, 

moderately  thick  leather  suppled   with    emery  ;   and  polishers  soft  thin 
leather  employed  with  dry  crocus. 

Thirdly.  Polishers  are  wheels  covered  with  thin  soft  leather,  and  supplit 
with  crocus  which  is  rubbed  on  dry,  and  without  the  intervention  of  glue 
oil.     In  Sheffield  one  kind  of  leather  is  tanned  expressly  for  polishers,  it 
being  important  that  the  whole  of  the  grease  should  be  extracted,  as  if  any 
remain  in  the  leather  it  will  not  polish  properly.     The  polishers  are  used 
alone  for  steel,  and  with  very  small  velocity. 

52. — THE  SMALLEST  BUFF  WHEELS,  called  bobs,  are  used  in  polishing  the  insides 
of  the  bowls  of  spoons — they  are  simply  disks  of  leather,  nearly  an  inch 
thick,  known  as  sea  cow  or  bull  neck  ;  they  are  perforated  so  as  to  be 
mounted  on  spindles,  and  are  turned  of  a  nearly  globular  form.  See  ALBATA. 

53. — BUFF  WHEELS  AND  OTHER  LEATHER  WHEELS,  WITH  WOODEN  CENTERS 
differ  much  in  size,  those  for  cutlers  usually  measure  from  ^  to  4  inches  wide 
by  4  to  20  inches  diameter,  although  they  are  sometimes  of  twice  that  diameter ; 
they  have  wooden  centers  or  disks  usually  cut  out  the  plankway  of  the  grain, 
in  similar  woods  to  those  used  for  glazers,  but  they  are  better  when  con- 
structed of  various  pieces  in  sectors,  the  best  mode  being  that  recommended 
in  article  41,  or  two  layers  of  sectors  each  consisting  of  about  sixteen  pieces 
and  glued  up  so  as  to  break  joint.  The  largest  of  these  wheels,  say  those 
exceeding  two  feet  diameter,  are  generally  made  up  of  one  set  of  middle 
sector-like  pieces,  screwed  fast  between  two  circular  iron  plates  which  are 
themselves  keyed  on  to  the  spindle,  and  then  a  set  of  felloes  is  nailed  or 
screwed  around  the  periphery  on  each  side  ;  making  the  thickness  out  to 
three,  four,  or  even  five  inches.  When  the  wood  centers  have  been  con- 
structed according  to  some  of  the  above  modes,  and  turned  cylindrical  or 
rounded  as  the  case  may  be,  they  are  turned  smooth  on  the  edges  and  then 
covered  with  one  thickness  of  leather. 

54. — IN  COVERING  THE  WHEELS,  the  wood,  and  also  one  side  of  the  leather,  are 
plentifully  glued,  the  extremity  of  the  leather  is  fixed  down  by  two  or  three 
nails  driven  a  little  way  into  the  wooden  disk,  the  leather  is  stretched  tight 
and  nailed  at  short  intervals,  and  its  other  end  is  also  fixed  down,  and  when 
the  entire  surface  is  covered  with  one  strip  if  possible,  the  glue  is  allowed  to 
dry.  It  is  a  matter  of  great  importance  that  the  ends  of  the  leather  should 
be  made  to  butt  closely  one  to  the  other  to  make  good  joints,  otherwise  the 
work  jumps  when  a  bad  joint  passes  beneath  it.  The  nails  are  afterwards 
withdrawn,  the  leather  is  turned  true  and  regular  with  a  flat  chisel.  Some- 
times the  glazers  are  required  to  be  very  hard,  and  in  this  case  the  leather  is 
soaked  in  water  for  a  few  hours  before  being  glued  on  the  wheel,  it  is  then 
secured  as  above  whilst  in  the  wet  condition,  and  in  drying  the  leather  con- 
tracts and  becomes  considerably  harder. 

Buff  Wheels  even  of  the  small  diameter  of  10  or  12  inches  are  frequently 
made  three  or  four  inches  wide,  and  covered  with  soft  leather  half  an  inch 
thick.  In  such  cases  the  thickness  of  the  wood  centers  is  also  very  nearly 
three  or  four  inches,  or  the  width  of  the  leather,  whichliowever  is  allowed  very 


AND    PROCESSES    FOR    GRINDING    AND    POLISHING.  1120 

slightly  to  project,  and  the  sides  of  the  wood  are  considerably  hollowed  in 
the  sweep  of  a  circle  from  the  edge  to  the  center  to  allow  the  works  to  be 
turned  round  on  the  edge  of  the  leather  in  reaching  into  hollow  and  rounded 
angles,  as  already  noticed  the  buff  wheels  are  used  either  with  Trent  sand  or 
rottenstone  mixed  with  oil,  and  for  various  materials  excepting  steel. 

Emery  Wheels,  when  the  leather  with  which  they  are  covered  has  been 
turned  smooth,  are  brushed  over  with  glue,  rolled  in  a  heap  of  dry  emery 
powder,  and  afterwards  on  a  smooth  board  to  consolidate  the  head  and 
make  the  periphery  smooth. 

55. — COARSE  EMERY  WHEELS  are  always  used  dry,  and  they  give  off  a  splendid 
display  of  sparks  with  some  of  the  risk  of  overheating  the  work  that  attends 
the  use  of  the  dry  grindstone  ;  the  finer  emery  wheels  are  sometimes  used 
just  as  explained  with  the  wooden  wheels,  namely  they  are  dressed  with  the 
emery  cake,  and  bouldered  down  with  the  flint,  to  bring  the  head  to  a 
smooth  and  regular  condition. 

Tool  makers  use  the  buffs  or  glazers  immediately  after  the  grindstone,  and 
select  the  coarse  and  fine  buffs  according  to  the  degree  of  finish  required. 
It  may  be  observed  the  dry  wheels  give  the  brighter  gloss,  but  do  not  gene- 
rally leave  the  work  so  smooth  as  those  which  are  greased. 

56. — IN  RENEWING  THE  FACE  OF  THE  EMERY  WHEEL,  or  in  putting  on  a  "  new 
head,"  the  wheel  is  wetted  with  a  sponge  and  cold  water,  and  allowed  to  soak 
for  about  an  hour,  the  used  emery  is  then  scraped  off  with  an  old  knife,  and 
the  surface  of  the  leather  is  made  somewhat  rough  ;  after  which  it  is  again 
glued,  and  rolled  first  on  the  emery  and  then  on  a  flat  board  as  originally. 
It  is  useless  to  attempt  "  to  put  one  head  upon  another,"  or  to  apply  new 
emery,  until  that  which  has  been  used  has  been  thoroughly  scraped  off. 

57.  —  THE  POLISHERS  FOR  RAZORS  AND  FINE  CUTLERY  are  soft  leather  wheels 
charged  with  crocus,  which  are  always  used  dry.  It  is  necessary  that  both 
the  polisher  and  blade  should  be  hot,  as  without  a  moderate  and  equal  degree 
of  heat,  short  however  of  that  producing  a  colour  on  the  steel,  the  process 
does  not  succeed,  and  a  good  polish  is  not  produced.  It  is  therefore  usual 
with  some  workmen  before  commencing  work  to  take  a  piece  of  razor  steel, 
which  is  held  against  the  revolving  polisher  to  prepare  it  for  the  work  itself, 
by  crushing  and  regulatir,  •  the  powder  with  which  the  polisher  is  charged. 

58. — ACTION  OF  THE  POLISHER. — Although  the  polisher  is  made  to  revolve  much 
more  slowly  than  the  other  wheels,  the  razor  is  moved  to  and  fro  from  end 
to  end,  very  quickly  and  with  considerable  pressure,  to  distribute  the  heat 
equally  ;  and  the  blade  is  not  drawn  slowly  across  and  off  as  in  lapping,  on 
the  contrary  the  work  is  moved  endlong  actively,  and  pulled  off  quickly.  In 
examining  the  work,  the  polished  part  is  occasionally  wiped  clean  with  the 
patch  or  thick  piece  of  cloth  or  felt,  which  serves  both  to  protect  the  fingers 
from  the  heat  of  the  blade,  and  also  to  supply  the  polisher  with  crocus,  as 
the  patch  is  dabbed  upon  a  small  quantity  of  dry  crocus  close  at  the  work- 
man's hand,  and  is  then  rubbed  on  the  polisher,  to  transfer  the  powder  to 
the  wheel. 


1121         DESCRIPTIVE    CATALOGUE    OF    APPARATUS,    MATERIALS, 

Occasionally  the  surface  of  the  polisher  becomes  very  hard  from  being 
somewhat  scorched  by  the  heat  generated  in  polishing,  and  its  surface  is 
then  more  or  less  filled  with  scratchy  lines  which  disfigure  the  blade,  at  such 
times  the  wheel  is  stopped,  and  the  face  of  the  polisher  is  roughed  up,  or 
thoroughly  scraped  with  an  old  razor  blade  or  knife  as  in  erasing  writing,  in 
order  to  remove  all  the  old  head  or  polishing  stuff,  and  render  the  leather  a 
little  rough,  and  quite  soft  ;  after  which  the  polisher  is  recharged  by  means  of 
the  thumb  or  patch. 

59. — THE  FLAT  SIDES  OF  WHEELS  are  not  often  covered  with  buff  leather  except 
by  lapidaries,  but  in  imitation  thereof  glass  and  emery  paper  are  frequently 
glued  on  flat  chucks  of  wood  and  used  for  finishing  the  flat  surfaces  of  small 
works  in  the  metals,  woods,  ivory,  and  other  substances,  and  Mr.  Larkin 
dusted  the  naked  wood  with  a  covering  of  pulverised  flint,  as  noticed  in  the 
previous  article  on  FLINT. 

60. — A  FLAT  POLISHING  MACHINE  actuated  by  rotary  motion  is  used  in  America 
for  flat  works,  such  as  brass  hinges,  parts  of  locks  and  other  metal  works. 
The  principal  part  consists  of  an  endless  strap  of  leather,  which  is  put  in 
motion  by  its  encircling  a  foot  wheel  as  in  a  lathe,  but  the  strap  instead  of 
giving  motion  to  a  pulley,  passes  over  and  in  contact  with  a  narrow  flat  board, 
the  edges  of  which  are  rounded  or  furnished  with  small  cylindrical  rollers  to 
lessen  the  friction,  sometimes  two  oblong  holes  are  simply  made  in  the  bench. 
The  strap  is  charged  with  emery  glued  on  exactly  as  in  the  emery  wheels  or 
buffs.  The  work  when  applied  on  that  part  of  the  strap  which  is  flowing 
over  the  flat  surface  of  the  board  is  polished  with  considerable  rapidity  and 
a  tolerable  approach  to  a  plane  surface. 

SECTION  F — WHEELS  OF  CLOTH,  OB  CLOTH  AND  LIST  WHEELS. 

61. — THE  CLOTH  USED  FOR  WHEELS  is  usually  thick  woollen  cloth  such  as  that  for 
white  great  coats,  and  the  blankets  of  printing  machines,  felted  cloths  are 
likewise  used.  Sometimes  the  cloth  or  felt  is  simply  glued  around  the  edge 
or  upon  the  face  of  the  wooden  wheels  precisely  the  same  as  in  buff  wheels, 
and  is  employed  for  similar  purposes. 

62. — OPTICIANS'  CLOTH  TOOLS,  consist  of  a  circular  piece  of  cloth  cemented  by 
means  of  pitch  upon  the  surface  of  one  of  their  brass  concave  or  convex 
tools  of  the  required  curvature,  the  cloth  if  new  is  seared  with  a  hot  iron  to 
remove  the  nap  before  it  is  cemented  down. 

Sometimes  the  opticians'  metal  tools  are  covered  with  a  broad  strip  of  thick 
silk  or  lute  string,  which  is  folded  around  the  edges  and  cemented  at  the 
back  of  the  tool.  The  cloth  and  silk  tools  are  always  used  with  putty 
powder.  See  the  articles  LENSES  Chap.  XXXIII.  Sect.  4. 

63. — THE  LAPIDARIES  CLOTH  MILL  is  a  face  wheel  having  an  annular  surface  about 
two  inches  wide,  there  is  first  a  center  of  wood  of  about  6  inches  diameter, 
then  a  spiral  coil  of  wide  list  or  cloth  which  is  wound  up  closely  until  the 
diameter  of  the  cloth  becomes  about  10  inches.  The  cloth  is  secured  partly 
by  tacks  driven  first  into  the  wood  centers,  and  then  by  small  nails  driven 


AND    PROCESSES    FOR    GRINDING    AND    POLISHING.  1122 

into  the  plate  of  wood  that  forms  the  back,  and  the  outer  coil  is  nailed  around 
the  edge  of  the  principal  disk,  so  that  the  whole  forms  an  annular  face 
with  a  loose  pliant  surface,  the  top  of  which  is  dressed  level  with  an  iron 
heated  to  a  dull  red. 

The  list  or  selvedge  of  woollen  cloth  is  commonly  used,  and  as  this  is 
thicker  on  one  edge  than  the  other,  it  is  the  practice  of  many  lapidaries  to 
roll  on  two  coils  at  once  by  aid  of  two  individuals,  the  thick  edge  of  the  one 
coil  being  downward  and  of  the  other  upwards  ;  this  mode  equalizes  the  ten- 
sion and  prevents  the  list  gathering  up  as  a  cone — and  in  this  case  it  is  only 
usual  to  nail  the  list  at  the  beginning  and  ending  of  the  coil. 

The  list  wheel  is  employed  generally  with  pumice-stone  and  water,  and 
from  its  elasticity  it  yields  admirably  to  the  curved  surface  of  shells  and 
stones  ;  it  is  also  employed  for  plane  surfaces  011  many  soft  substances,  as 
explained  under  the  article  ALABASTER  in  this  Catalogue. 
>4. — IVORY  WORKERS'  LIST  WHEELS  consist  of  10  to  20  circular  pieces  of 
cloth  screwed  fast  between  two  disks  of  wood  about  2  or  3  inches  smaller 
than  the  cloth,  which  therefore  forms  a  pliant  edge  projecting  an  inch  or 
upwards  beyond  the  wood,  and  which  is  well  adapted  to  the  curvilinear  sur- 
face of  umbrella  or  parasol  handles,  and  many  such  works — the  wheel  is  fed 
with  Trent  sand,  loam  or  chalk,  or  it  is  better  to  have  one  wheel  for  each  of 
these  substances.  See  IVORY. 


SECTION  G. — WHEELS  OF  BRISTLES,  OR  WIRE,  OR  BRUSH  WHEELS. 

. — WHEEL  BRUSHES  OR  BRUSH  WHEELS  are  very  largely  employed  in  the  arts  ; 
they  are  made  both  hard  and  soft,  and  of  all  diameters  from  about  2  to 
8  inches,  with  the  hairs  placed  radially  so  that  the  outer  rows  lean  a  little 
towards  the  center  to  give  them  more  stability. 

Wheel  brushes  are  used  with  emery,  crocus,  rottenstone,  putty  powder, 
whiting,  and  in  fact  all  the  polishing  powders  both  with  oil  and  dry,  and  they 
are  employed  for  curved,  indented,  chased,  open  and  pierced  works,  but  it 
is  to  be  remembered  the  brush  rapidly  obliterates  keen  angles,  the  preserva- 
tion of  which  requires  particular  care  and  patience,  and  the  employment  of 
hard  buffs  or  the  wood  and  metal  polishers  already  described — as  the  greater 
the  degree  of  exactness  that  is  required  in  the  angles  and  edges  of  polished 
works,  the  greater  should  be  also  the  degree  of  hardness  in  the  face  of  the 
grinders  and  polishers  employed. 
66. — WHEEL  BRUSHES  MADE  OF  IRON  AND  BRASS  WIRE,  instead  of  hairs,  are  occa- 
sionally used  after  the  manner  of  scratch  brushes  made  of  metal  wire,  and 
for  the  same  general  purposes  ;  as  for  cleaning  and  scratching  the  metals 
preparatory  to  gilding  and  silvering,  but  not  for  polishing.  The  ends  of  the 
wires  are  a  little  curved  to  soften  the  abruptness  with  which  they  would 
otherwise  meet  the  work. 

\  WHITING  is  common  chalk,  ground,  washed  for  the  separation  of  sand  and  other 
impurities,  and  dried  in  lumps.  See  CHALK. 

VOL  III.  H 


1123        DESCRIPTIVE    CATALOGUE    OF    APPARATUS,    MATERIALS, 

WOODS. — Many  variations  will  be  met  with  in  the  modes  by  which  the  woods  are 
polished,  and  which  depend  greatly  on  the  qualities  of  the  woods  themselves, 
as  to  hardness,  fibre  and  colour ;  consequently  under  this  head  it  is  preferred 
nearly  to  follow  the  arrangement  of  the  turnery  and  other  woods,  enume- 
rated in  the  tabular  view  in  page  70  of  the  first  Volume. 

TURNED  WORKS. 

] . — WOODS  OF  SOFT  GRAIN  AND  LIGHT  COLOURS,  such  as  alder,  ash,  small  beech  and 
birch  wood,  sallow,  willow,  and  also  holly,  horse  chesnut,  sycamore  and  some 
others,  which  woods  are  used  respectively  for  common  toys,  and  the  best 
Tunbridge  wares,  are  in  many  cases  so  smoothly  turned  as  not  to  require  any 
polishing  whatever,  or  at  most,  only  the  friction  of  a  few  of  their  own 
shavings. 

The  less-experienced  may  find  it  necessary  previously  to  employ  glass 
paper,  and  it  is  then  desirable  to  polish  the  work  first  whilst  it  revolves  in 
the  one  direction,  which  lays  down  flat  such  of  the  loose  filaments  as  are  not 
polished  off ;  and  then  by  reversing  the  motion  of  the  lathe,  these  parts  are 
as  it  were  brushed  up,  and  generally  removed.  The  alternating  motion  of 
the  pole  or  spring  lathe,  is  therefore  desirable  in  polishing  such  woods.  A 
few  shavings  are  mostly  used  after  the  glass  paper  to  remove  the  loose  dust 
and  brighten  the  surface.  Many  of  the  toys  and  works  here  referred  to  are 
coated  with  the  white  sandarac  varnish,  and  some  few  are  subsequently 
polished. 

2. — WOODS  OF  MEDIUM  HARDNESS  AND  COLOUR,  namely,  apple  tree,  plum  tree,  and 
old  beech  wood,  box,  elm,  oak,  walnut,  and  also  mahogany  and  some  others, 
although  in  general  turned  with  the  tools  for  soft  woods,  and  in  the  same 
manner  as  the  first  group,  are  polished  in  almost  every  case  with  glass  paper. 
They  are  then  in  general  coated  either  with  boiled  linseed  oil,  which  is 
applied  with  a  brush  or  rag,  allowed  to  soak  in  for  a  short  time,  and  is  after- 
wards rubbed  off  with  shavings  ;  or  else  they  are  covered  thinly  with  bees- 
wax dissolved  in  turpentine,  and  applied  on  a  flannel.  As  much  as  possible 
of  the  bees- wax  is  afterwards  rubbed  off  with  a  clean  flannel,  to  prevent  the 
stickiness  that  occurs  from  an  undue  quantity  of  the  dissolved  bees-wax, 
which  never  thoroughly  hardens.  Some  workmen  judiciously  add  a  little 
powdered  resin  to  the  bees-wax  and  turpentine,  this  gives  a  little  more  con- 
sistency to  the  wax  and  lessens  its  stickiness,  but  the  quantity  should  be 
moderate. 

Some  workmen  use  the  wax  in  its  natural  state,  and  rub  it  in  by  softening 
it  with  the  friction  caused  by  a  stick  of  deal  wood,  applied  successively  over 
the  surface  of  the  work,  and  afterwards  remove  as  much  as  possible  of  the 
wax  with  a  flannel.  For  woods  that  have  been  stained  black,  the  black  wax 
or  composition  prepared  for  the  shoemakers,  (and  called  heel-ball,)  is  almost 
always  thus  applied,  unless  indeed  the  works  are  lackered  after  the  manner 
of  French  polishing. 

3.— WOODS  OF  THE  HARDEST  GRAIN  AND  DARKEST  COLOURS,  and  some  others 
such  as  the  foreign  hardwoods  for  turnery  enumerated  in  the  tabular  view 


AND    PROCESSES    FOR    GRINDING    AND    POLISHING.  1124 


on  page  70,  vol.  i.,  are  sometimes  polished  precisely  after  one  of  the  modes 
already  described,  in  other  cases  they  are  lackered,  the  mode  of  fulfilling 
which  will  be  afterwards  described,  but  when  the  lacker  is  used  it  should 
be  applied  directly  after  the  glass  paper,  and  without  either  oil  or  bees- wax 
having  been  used  previously. 

It  should  however  be  observed  that  careful  workmen  place  but  little 
reliance  on  the  advantage  to  be  derived  from  polishing,  as  in  truth  the  work 
should  be  left  so  smooth  and  exact  from  the  turning  tool  as  to  require  little 
or  nothing  to  be  afterwards  done  to  it.  The  practice  employed  by  the 
mechanist  of  rubbing  the  emery  or  glass  paper  face  to  face  to  abrade  any 
coarser  particles  is  here  likewise  desirable,  and  also  that  of  wrapping  the 
papers  around  a  parallel  slip  of  wood  in  polishing  flat  surfaces  and  some 
others,  as  this  tends  to  preserve  the  keenness  of  the  angles  and  fillets  of 
works  turned  in  the  woods.  In  polishing  within  the  bottom  or  lid  of  a  snuff 
box,  it  will  be  found  advantageous  to  wrap  the  fine  polishing  paper  around 
a  small  cubical  block  of  wood,  one  or  two  of  the  faces  of  which  are  rounded 
or  made  cylindrical ;  this  will  tend  to  lay  an  even  flat  grain  over  the  work. 
4. — HARDWOODS  POLISHED  WITH  TRIPOLI. — A  lustre  that  may  be  termed  a  natura 
polish  is  given  to  some  of  the  hardwoods  of  close  grain,  as  in  the  best  flutes 
made  of  cocoa  wood  and  ebony,  and  some  other  works  ;  that  is  to  say  the 
surface  of  the  wood  is  polished  entirely  by  abrasion,  the  same  as  the  metals, 
marble,  and  many  other  materials.  The  process  is  sometimes  conducted 
with  tripoli  powder,  at  other  times  with  Dutch  rush ;  and  it  is  needful  in 
each  case  that  the  work  should  have  been  smoothly  turned,  and  then  rubbed 
with  fine  glass  or  emery  paper,  which  latter  is  frequently  preferred. 

A  moderate  quantity  of  yellow  tripoli  is  placed  on  flannel  slightly  mois- 
tened with  oil,  and  applied  just  like  glass  paper,  the  motion  of  the  lathe  being 
occasionally  changed  in  direction,  and  sometimes  stopped,  whilst  the  flannel 
is  rubbed  lengthways,  to  diversify  the  direction  of  the  friction  thus  applied. 
It  is  desirable  not  to  use  a  second  supply  of  tripoli,  unless  at  an  early  stage, 
but  to  allow  the  powder  to  become  embedded  in  the  flannel,  and  worn  down 
to  a  smooth  face,  on  which  account  but  little  oil  should  be  used.  The  tripoli 
then  becomes  gradually  finer  and  drier,  and  with  careful  management  will 
produce  a  surface  entirely  free  from  scratches  and  highly  polished,  without 
the  adventitious  aid  of  lacker  ;  this  mode  produces  a  far  more  durable 
surface,  wood  being  a  much  harder  substance  than  the  shell  lac,  the  basis  of 
the  varnish  for  hardwood. 

. — HARDWOODS  POLISHED  WITH  DUTCH  RUSH. — A  dozen  or  more  short  pieces  or 
joints  of  the  rush  just  divested  of  the  knots  and  tied  up  at  the  ends  as  a  faggot 
are  used  with  water,  applying  all  sides  of  the  rush  to  wear  it  down  smooth 
alike  ;  and  in  this  case,  as  in  the  last,  the  same  polisher  is  continually  used 
throughout  the  process,  in  order  that  it  may  become  finer  with  the  progress 
of  the  polishing.  After  a  sufficient  period,  and  when  the  rush  feels  inactive, 
it  is  laid  by  and  allowed  to  dry,  when  it  is  again  used  in  the  dry  state,  and 
serves  to  bring  up  a  polish  nearly  or  quite  equal  to  that  produced  by  the 
tripoli.  Some  artizans  employ  subsequently  to  the  rush,  putty-powder  or 

H2 


1125         DESCRIPTIVE    CATALOGUE    OF    APPARATUS,    MATERIALS, 

rottenstone,  but  this  is  only  admissible  when  the  surface  of  the  wood  is  so 
smooth  and  dark  as  to  be  incapable  of  retaining  the  powders  in  its  pores,  or 
of  becoming  stained  by  tfiem. 

6. — TURNED  WORKS  CARVED  AND  ORNAMENTED  with  the  eccentric  chuck,  or 
revolving  cutters,  &c.,  do  not  admit  of  any  polishing  beyond  the  use  of  a 
clean  dry  brush  ;  sometimes  a  drop  of  oil  is  placed  on  the  brush,  but  the 
oil  although  it  may  leave  a  temporary  gloss,  is  eventually  absorbed  in  the 
wood,  and  renders  the  surface  more  dull  than  before. 

Occasionally  the  ornamented  works  are  coated  slightly  with  thin  varnish 
laid  on  with  a  brush,  this  is  not  to  be  recommended,  and  unless  the  patterns 
are  very  bold,  and  the  varnish  is  very  dexterously  applied,  it  is  almost  certain 
to  fill  in  the  hollows  to  a  degree  that  is  highly  prejudicial  to  the  appearance 
of  the  work. 

That  sharp  tools  and  proper  treatment  completely  obviate  the  necessity  o: 
any  polish  on  engine  turned  works  in  hardwood,  beyond  that  of  a  dry  brushx 
is  abundantly  proved  by  several  of  the  most  tasteful  and  finished  specimens 
ever  executed,  which  were  the  work  of  a  lady,  and  are  in  the  author's  pos- 
session. The  proper  course  was  pursued  -in  their  formation  ;  namely,  that 
of  polishing  very  highly  the  facets  forming  the  cutting  edges  of  the  tools,  in 
the  manner  that  is  elsewhere  explained,  and  allowing  the  tool  to  cut  gra- 
dually, or  without  plunging  it  too  rapidly  or  too  rankly  into  the  work. 


FLAT  WORKS. 

7. — FLAT  WORKS  IN  WOOD. — The  majority  of  the  joiners'  works  wrought  with 
the  plane,  and  others  executed  with  the  file,  come  under  this  denomination. 
Their  flat  surfaces  are  in  general  scraped  with  the  ordinary  joiner's  scraper, 
a  thin  plate  of  sheet  steel,  the  edge  of  which  is  sharpened  on  the  oil-stone 
and  burred  up  with  the  burnisher.  (See  page  484,  vol.  ii.,  fig  331.)  After- 
wards the  wood  is  cleaned  with  glass  paper,  of  two  or  more  sizes,  wrapped 
around  a  flat  piece  of  cork  glued  on  a  block  of  wood  about  3x4  inches 
square,  or  on  a  piece  of  wood  on  the  flat  surface  of  which  one  thickness  of 
woollen  cloth  is  stretched  and  nailed  around  the  edges  which  acts  with 
greater  accuracy  than  the  elastic  cork,  and  keeps  the  work  flatter. 

8. — SMALL  FLAT  WORKS  IN  WOOD  are  often  rubbed  upon  the  sheet  of  glass  paper, 
which  is  then  laid  on  the  flat  bench  or  other  board — a  practice  analogous  to 
that  pursued  by  watchmakers  and  others.  In  some  cases  also  small  flat  sur- 
faces in  wood  are  finished  on  face  wheels,  or  plane  disks  of  wood  on  which 
glass  paper  is  glued  ;  this  practice  is  somewhat  common  for  the  mechanism 
of  piano-fortes,  and  many  years  back  an  analogous  method  was  pvirsued  by 
Mr.  Larkin,  which  is  described  under  the  head  FLINT. 

9. — POLISHED  FLAT  WORKS.— It  may  be  generally  said  that  the  several  modes  of 
polishing,  already  described  in  reference  to  turned  works  of  wood,  are  al 
more  or  lest  practised  also  in  flat  works  ;  indeed,  they  were  always  usec 
until  comparatively  of  late  years,  when  the  so-called  French  polish,  (to  be 
hereafter  spoken  of,)  has  nearly  obtained  a  monopoly  in  the  embellishment  of 


AND    PROCESSES    FOR    GRINDING    AND    POLISHING.  1126 

furniture  and  other  works  ;  the  carved  surfaces  of  which  are  still,  however, 
mostlv  varnished  with  a  brush  as  in  painting,  and  not  by  attrition.  But  the 
old  fashioned  polish  due  to  linseed  oil,  applied  daily  for  a  year  or  two, 
although  tedious,  produced  an  equally  beautiful  and  far  more  lasting  polish, 
although  it  must  be  admitted  the  oil  has  the  effect  of  rendering  the  woods 
somewhat  darker.  In  conclusion  of  these  remarks  the  reader  is  referred  to 
the  article  MARQUETRY  in  this  Catalogue. 

WROUGHT  IRON. — The  parts  of  machinery  made  of  wrought  iron  are  polished 
as  described  in  the  general  article  MACHINERY  in  this  Catalogue :  two  other 
examples  are  alone  here  given. 

The  parts  of  stoves  and  similar  works  in  wrought  iron,  are  sometimes 
ground,  but  in  general  they  are  filed,  draw-filed,  rubbed  with  an  emery 
rubber,  and  burnished  with  the  two  handed  burnisher  having  a  stirrup  for 
the  foot  ;  as  in  such  works  the  glittering  polish  on  a  comparatively  scratchy 
surface,  is  considered  to  be  good  enough  for  the  purpose. 

Round  Tcnols,  crooked  arms,  bows  of  keys,  stirrups,  bridle  bits,  and  pieces 
free  from  sharp  angles,  are  often  polished  by  wrapping  once  or  twice  around 
them,  a  piece  of  soft  rope  or  string  smeared  with  the  polishing  stuff ;  and 
by  using  a  sawing  motion  with  the  two  hands,  a  considerable  friction  is  applied 
all  around  the  objects.  The  screws  of  corkscrews  are  mostly  thus  dressed. 

ZINC. — Door  plates  made  of  rolled  zinc  are  cut  out,  scraped  to  a  clean  surface, 
hammered  flat  and  then  planished,  after  which  they  are  by  some  workmen 
smoothed,  1st,  with  a  stick  of  blue  stone  and  water  ;  2ndly,  with  emery  paper 
wrapped  on  a  piece  of  wood  or  cork,  and  moistened  with  oil  j  3rdly,  with 
rottenstone  and  oil  on  a  coil  of  list. 

Other  workmen  employ  immediately  after  the  scraper,  1st,  pumice-stone, 
either  in  the  lump  or  powder  ;  2ndly,  flour  emery  and  oil  on  a  flat  woollen 
rubber  ;  and  3rdly,  rottenstone  in  the  same  manner. 

ZINCOGRAPHIC  PLATES  FOR  PRINTING. — In  order  to  give  these  the  fine 
grained  surface  required  in  this  branch  of  the  graphic  art,  they  are,  1st, 
rubbed  with  ordinary  sand,  and  2ndly,  with  fine  sifted  sand,  the  rubber  is  of 
list  rolled  up  tight  and  used  with  water ;  the  zinc  plate  is  then  ready  to  receive 
the  drawing  which  is  made  with  the  ordinary  lithographic  chalk  upon 
the  plate,  or  is  transferred  from  the  transfer  paper  and  fixed  by  an  acid 
preparation. 

Zinc  plates  are  equally  susceptible  with  lithographic  stones  of  the  transfer 
process,  and  which  by  Wood's  patent  method  of  "  Anastatic  Printing,"  may 
be  employed  in  producing  fac-simile  copies,  by  transfer,  of  engravings  or 
books  of  the  very  earliest  dates  hi  their  respective  arts. 


ZIRCON  is  the  generic  name  of  three  varieties  of  gems  known  as  the  Hya- 
cinth, the  Jargoon,  and  the  Zirconite,  they  are  sometimes  so  hard  as  to 
require  to  be  cut  into  facets  with  diamond  powder  the  same  as  Sapphires. 
«  The  exposure  of  some  varieties  to  heat,  deprives  them  of  their  colour,  and 
they  are  said  to  have  been  sold  in  that  state  in  place  of  the  diamond." 


Z1J 


CHAPTER  XXXII. 

GRINDING  AND  SHARPENING  CUTTING  TOOLS. 


SECT.    I. GRINDING    CUTTING    TOOLS    ON    THE    ORDINARY    GRINDSTONE. 

THE  various  apparatus,  materials,  and  processes,  employed  in 
grinding,  and  polishing,  having  been  generally  described  in  the 
preceding  Catalogue,  it  will  be  only  necessary  in  the  present 
chapter,  to  offer  a  few  examples  of  the  grinding  and  sharpening 
apparatus  commonly  employed  by  amateurs,  together  with  a  brief 
notice  of  the  modes  of  restoring  the  edges  of  the  most  usual  tools, 
and  which  will  serve  to  convey  a  sufficiently  precise  idea  of  the 
modes  of  sharpening  those  not  described,  as  the  edges  of  all 
cutting  tools  may  be  considered  as  either  rectilinear,  or  circular, 
or  combinations  of  the  two  forms. 

The  present  chapter  will  therefore  contain  one  section  on  the 
grinding  of  cutting  tools  on  the  ordinary  grindstone,  one  section 
on  the  sharpening  of  cutting  tools  on  the  oilstone,  and  one  section 
on  setting  razors,  in  all  of  which  cases  scarcely  any  guides  are 
employed,  but  the  tool  is  applied  with  the  unassisted  fingers. 
These  will  be  followed  by  one  section  on  sharpening  cutting  tools 
with  artificial  grinders,  in  which  from  the  greater  amount 
exactness  generally  required,  guides  of  various  kinds  are  usuall; 
employed,  and  the  chapter  will  conclude  with  a  few  miscellaneous 
examples  of  the  less  usual  modes  of  restoring  the  edges  of  cutting 
tools. 


Of  all  the  tools  in  the  workshop  whether  of  the  amateur  or 
the  practical  man,  the  absence  of  the  grindstone  would  be  th< 
most  severely  felt,  without  it  the  restoration  of  the  edges  of  th( 
tools  would  be  scarcely  possible,  and  upon  their  perfection  much 
of  the  practical  success  of  cutting  processes  depends. 

Sharp  tools,  produce  with  the  least  expenditure  of  time,  sui 
faces  so  nearly  finished  as  to  require  but  very  little  polishing 
whereas  blunt  tools  leave  the  lines  and  mouldings  less  accurate!] 


PRIMITIVE    GRINDSTONES.  1128 


defined,  and  the  additional  friction  or  polishing  employed  to 
gloss  over  the  defects  makes  a  bad  case  worse,  and  obliterates 
all  the  keen  edges  that  would  impart  to  the  work  a  defined  and 
exact  character. 

The  ordinary  mischief  in  polishing  is  excess,  and  the  amateur 
is  most  strenuously  counselled  to  polish  the  tool  upon  the  oil- 
stone, or  other  fine  abrasive  employed  for  setting  the  edge,  and 
he  may  be  assured  that  it  will  then  not  only  cut  in  a  much  more 
agreeable  manner,  but  likewise  that  it  will  impart  its  relative 
degree  of  perfection  to  the  work,  in  like  manner  that  the  coin  or 
medal  is  polished  by  the  bright  and  accurate  surface  of  the  die, 
and  not  by  any  subsequent  process. 

The  primitive  tools  whether  of  stone,  wood,  bone,  or  metal, 
were  probably  sharpened  by  rubbing  them  on  flat  gritty  stones, 
a  method  still  resorted  to  in  the  absence  of  other  means,  although 
when  the  substances  are  hard  and  much  is  required  to  be  ground 
away,  it  is  exceedingly  tedious  ;  and  perhaps  one  of  the  earliest 
efforts  at  mechanical  contrivance,  coeval  with  the  introduction  of 
the  draw  well,  and  the  potter's  wheel,  (also  a  revolving  flat  stone,) 
was  the  rotation  of  the  grindstone  upon  an  axis,  fixed  within  a 
central  aperture  cut  within  the  same,  and  now  often  denominated 
the  eye.  The  spindle  was  doubtless  supported  in  a  horizontal 
direction  in  notches  made  in  the  top  of  two  stakes  fixed  in  the 
ground,  or  in  some  simple  frame,  and  a  transverse  handle  was 
fixed  to  the  axis  to  enable  one  man  to  turn  round  the  stone, 
whilst  another  applied  to  its  surface  the  tool  to  be  ground. 

This  primitive  apparatus,  a  little  improved  in  its  mechanical 
details,  still  exists  in  almost  every  village  and  also  in  many 
workshops,  notwithstanding,  as  will  be  FlG 

shortly  shown,  that  a  far  more  economi- 
cal mode  for  tools  of  a  medium  size  has 
been  employed  for  at  any  rate  three 
centuries- 

Small  grindstones  not  exceeding  a  few 
inches  in  diameter,  are  commonly  fixed 
in  a  similar  manner  in  boxes  of  wood 
or  iron.  Fig.  1027,  represents  one  of 
these  of  about  one  foot  in  diameter,  the  bearings  of  which  are 
screwed  to  the  cast  iron  trough  ;  a  stone  of  this  diminutive  size 
may  be  turned  by  the  left  hand,  whilst  the  tool  supported  on 


1129 


VARIOUS    ARRANGEMENTS  OF 


the  iron  rest  is  held  in  the  right,  this  arrangement  is  usually 
adopted  for  small  tools,  such  as  those  employed  by  watchmakers, 
jewellers,  engravers,  and  others,  in  which  the  quantity  of  material 
to  be  removed  is  inconsiderable. 

The  succeeding  figure  is  copied  from  an  engraving  in  a  work 
by  Hartman  Schopperum,  printed  at  Frankfort  on  the  Maine  in 
1548.  In  this  case  the  stone  is  moved  by  a  treadle,  which  is  an 
admirable  plan  for  grindstones  from  about  twenty  to  forty  inches 
diameter,  that  are  intended  for  sharpening  tools,  as  the  weight 

FIG.  1028. 


of  the  stone  serves  as  the  fly  wheel,  and  the  whole  process  may 
be  carried  on  by  one  individual.  This  mode  is  less  common 
than  it  deserves  to  be,  the  treadle  should  however  be  extended 
beyond  the  crank  rod,  and  the  foot  should  be  applied  at  the 
opposite  end,  the  same  as  in  the  ordinary  turning  lathe. 

An  oval  tub  made  of  staves  like  a  barrel  is  sometimes  used  as 
a  trough,  its  diameters  should  be  about  as  two  to  one ;  the  axis 
of  the  stone  is  placed  across  the  shorter  diameter,  and  it  runs 
in  collars  of  hardwood  or  metal  fixed  to  the  sides  of  the  trough, 


FRAMES  FOR  GRINDSTONES. 


1130 


which  is  supported  at  a  convenient  height  upon  four  legs  ;  the 
treadle  is  joined  to  the  back  legs,  and  it  communicates  with  the 
crank,  which  overhangs  the  bearing  in  the  manner  of  the  last 
figure. 

Grindstones  are  also  fitted  up  in  a  variety  of  other  frames^ 
either  of  wood  or  metal.  The  ends  or  pivots  of  the  spindles  are 
either  cylindrical,  conical,  or  turn  between  conical  center  points. 
The  water-trough  is  stationary  in  some  cases,  in  others  it  is 
joined  to  the  frame  by  a  joint  or  hinge  at  the  one  extremity,  and 


FIG.  1029. 


1131  GRINDSTONES    DRIVEN    BY    TREADLES. 

supported  by  a  chain  at  the  other,  in  order  that  it  may,  from 
time  to  time,  be  lifted  up  to  moisten  the  edge  of  the  stone, 
which,  as  previously  explained,  should  never  be  allowed  to  rest 
in  the  water,  as  that  part  would  be  softened,  and  would  there- 
fore wear  away  more  rapidly  than  the  remainder,  and  hasten  the 
departure  from  circularity.  The  frame  is  generally  provided 
with  a  support  on  which  the  tool  or  the  hand  is  rested,  and 
also  with  a  splash-board  to  catch  the  wet  thrown  off  by  the 
centrifugal  force,  and  conduct  it  back  into  the  trough. 

Fig.  1029  represents  an  arrangement  suitable  for  grind- 
stones of  from  two  to  three  feet  diameter.  In  this  case  the 
frame  is  entirely  of  iron  ;  the  stone  is  worked  by  a  treadle 
leading  to  the  cranked  spindle,  mounted  between  centers ; 
and  instead  of  the  stone  being  fixed  to  the  spindle  by  wooden 
wedges,  which  are  liable  to  be  disturbed  from  their  original 
setting  by  extreme  change  from  wet  to  dry,  they  are  secured  by 
the  improved  plan,  introduced  by  Holtzapffel  &  Co.,  of  casting  a 
lead  center  in  the  eye  of  the  stone,  by  means  of  a  proper  mould, 
so  as  to  leave  a  central  and  cylindrical  aperture,  and  the  spindle 
is  turned  to  the  corresponding  diameter,  and  provided  with  a 
screw  and  nut,  which  press  the  stone  against  a  flange  on  the 
spindle,  which  has  a  pin  to  ensure  the  rotation  of  the  stone.  In 
this  manner  the  stone  is  fixed  with  great  solidity,  and  with  the 
power  of  removal  from  one  spindle  to  another,  when  the  reduc- 
tion of  the  diameter  of  the  stone  calls  for  the  change.  Fig.  1027 
is  also  mounted  upon  its  spindle  in  a  similar  manner.  The  rest 
for  the  tools  in  fig.  ]  029  admits  of  being  placed  at  any  height  or 
distance  from  the  stone  that  may  be  required,  and  a  leather  flap 
suspended  from  the  rest  serves  the  purpose  of  the  splash-board, 
mentioned  in  the  last  paragraph. 

A  small  grinding  and  polishing  machine  adapted  for  the  use  of 
the  amateur  is  represented  in  fig.  1030.  This  machine  is  fitted 
with  five  spindles,  two  of  them  have  grindstones,  the  one  for 
rough  usage,  the  other  to  be  reserved  for  the  more  particular 
tools,  the  three  other  spindles  are  fitted  with  a  metallic  lap  of 
lead  hardened  with  a  little  antimony,  a  buff  wheel  with  emery, 
and  a  circular  brush.  The  spindles  are  driven  by  an  iron  foot 
wheel  and  treadle,  somewhat  after  the  manner  of  a  lathe,  as 
explained  under  the  head  WHEELS  in  the  catalogue,  page  1104, 
article  7.  The  stones  of  about  the  diameter  of  7  inches  are 


GRINDING    AND    POLISHING    LATHE    FOR    AMATEURS. 


1132 


fixed  upon  roughened  iron  spindles  by  means  of  melted  lead 
poured  in  between  the  two ;   by  this  plan  such  small  stones  are 


FIG.  1030 


not  liable  to  be  split,  which  frequently  occurs  with  wooden 
wedges,  either  from  their  being  over  driven  in  the  first  instance, 
or  from  their  subsequent  expansion  by  wet. 

The  spindles  were  formerly  made  with  centers  at  each  end, 
and  a  pulley  for  every  spindle,  but  they  are  now  made  with  a 
center  point  at  the  one  extremity,  and  a  truncated  cone  with  a 


1133  GRINDING    AND    POLISHING    LATHE    FOR    AMATEURS. 

driving  pin  at  the  other,  and  the  spindles  work  respectively 
between  a  center  screw  and  a  hollow  notched  cone  fixed  in  front 
of  the  pulley,  which  is  free  to  revolve  upon  its  own  bearing, 
when  connected  by  the  band  with  the  foot  wheel  and  treadle 
beneath.  By  this  arrangement  which  is  somewhat  similar  to  the 
center  chuck  and  driver  of  the  common  turning  lathe,  the 
spindles  can  be  readily  exchanged,  by  unwinding  the  center 
screw,  without  the  displacement  of  the  band.  The  machine  is 
provided  with  two  iron  rests  for  the  tools,  that  are  each  appli- 
cable to  the  edges  of  the  grindstones  and  the  face  of  the  lap, 
they  are  of  different  bevils  and  susceptible  of  adjustment  by  the 
screw.  On  the  back  of  the  cast  iron  trough  is  mounted  a  water 
cistern  with  drip  valve,  the  water  from  which  falls  upon  the 
stone  slightly  in  advance  of  a  piece  of  tow,  held  in  contact  with 
the  stone  by  a  clamp,  this  effectually  prevents  the  water  from 
being  thrown  off,  by  the  centrifugal  action,  and  keeps  the  stone 
uniformly  moist.  A  box  at  the  back  of  the  frame  serves  to  con- 
tain the  polishing  powders,  brushes  and  scraper.  The  other 
parts  of  the  apparatus  will  be  sufficiently  explained  by  an 
inspection  of  the  figure. 

The  ordinary  cutlers'  wheel  and  the  large  grindstones  for  tools 
have  been  already  described  in  the  catalogue,  pages  1105  to 
1108,  and  their  arrangement  will  be  sufficiently  obvious  without 
the  aid  of  diagrams.  Large  stones  are  however  sometimes  fur- 
nished with  a  contrivance  called  a  dolly  bar,  for  adjusting  the 
height  of  the  water  in  the  trough  without  the  continual  neces- 
sity for  adding  small  quantities  to  maintain  it  at  the  most  suit- 
able level,  the  dolly  is  a  large  wooden  bar  suspended  from  a 
pulley  attached  to  the  splash  board,  and  partially  immersed  in 
the  water,  when  the  dolly  is  lowered  it  causes  a  corresponding 
elevation  of  the  water  so  as  just  to  reach  the  grindstone.  This 
contrivance  in  common  with  all  those  of  the  grinder  is  exceed- 
ingly simple,  and  although  dirty  the  grindery  is  often  very 
picturesque. 

The  restoration  of  the  edges  of  most  cutting  tools  for  wood 
and  soft  substances  is  effected  by  the  successive  action  of  the 
grindstone  and  oilstone,  the  former  being  employed  to  remove 
the  principal  bulk  of  the  material,  so  as  to  prepare  the  tool 
for  the  action  of  the  slower  but  more  delicate  oilstone,  which 


GENERAL    REMARKS    ON    GRINDING    TOOLS.  1134 

produces  a  much  keener  and  more  accurate  edge  than  can  be 
obtained  with  the  grindstone.  Tools  for  cutting  the  metals  and 
hard  materials  are  frequently  left  from  the  grindstone  without 
the  application  of  the  oilstone,  which  is  chiefly  resorted  to  for 
setting  a  smooth  edge  upon  the  finishing  tools. 

Tools  that  arc  required  to  possess  a  delicate  edge  of  a  definite 
form,  should  in  all  practicable  cases  be  ground  upon  the  one 
bevil  only,  the  second  face  then  admits  of  being  carefully  formed 
in  its  manufacture,  and  the  accuracy  thus  given  should  be  scru- 
pulously maintained,  as  it  is  clearly  much  easier  to  produce  the 
required  form  by  the  abrasion  of  the  less  important  face,  than 
when  both  angles  of  the  edge  have  to  be  renewed  every  time  the 
tool  is  sharpened.  For  example,  the  axe  and  chipping  chisel  which 
require  considerable  strength,  and  but  a  moderate  amount  of 
accuracy,  are  commonly  ground  with  two  bevils,  while  the  plane 
iron  and  paring  chisel,  which  require  accurate  edges  and  greater 
delicacy,  have  the  one  face  made  quite  level  in  the  first  instance, 
and  in  the  process  of  sharpening,  the  second  face  of  the  angle  is 
alone  operated  upon  ;  in  screw  tools,  and  moulding  tools  for 
turning,  this  is  still  more  imperative.  The  razor,  which  requires 
delicacy  of  edge  rather  than  accuracy,  is  sharpened  on  both 
faces,  but  in  this  case  as  will  be  shown  hereafter  the  back  of  the 
instrument  serves  as  a  guide  for  the  formation  of  the  edge. 

The  grindstone  should  be  kept  in  order  so  far  as  possible 
by  the  equal  distribution  of  the  wear ;  narrow  tools  especially, 
should  be  constantly  traversed  across  the  face  of  the  stone  to 
avoid  wearing  the  latter  into  ridges,  and  the  extreme  edges  of 
the  stone  should  be  exposed  to  their  fair  amount  of  work,  or 
otherwise  the  stone  will  become  hollow  and  unfitted  for  grinding 
broad  flat  tools.  By  the  equal  application  of  the  tools,  the  face 
of  the  stone  may  be  kept  tolerably  flat  with  but  little  recourse 
to  turning  or  hacking,  which  processes  have  been  explained  in 
the  preceding  catalogue  under  the  head  WHEELS,  articles  14  to 
17.  When  however  the  stone  loses  its  circularity,  or  becomes 
eccentric  from  being  worn  irregularly,  it  is  better  at  once  to 
rt  to  one  of  the  means  of  correction,  as  otherwise  the  stone 
ecomes  rapidly  worse,  and  the  difficulty  of  holding  the  tools 
steady  is  considerably  increased. 

As  a  more  scientific  way  of  keeping  grindstones  in  order,  it 
has  been  proposed  that  two  grindstones  should  be  mounted  with 


1135  GENERAL   REMARKS    ON    GRINDING    TOOLS. 

their  axes  parallel,  and  adjustable  by  a  screw  to  keep  their  sur- 
faces always  in  contact,  and  by  giving  them  different  surface 
velocities  they  would  respectively  abrade  and  correct  each  other, 
but  the  contrivance  although  simple  is  too  refined  for  the 
majority  of  the  grinders'  shops,  and  is  scarcely  required  for  the 
limited  purposes  of  the  amateur. 

The  flat  side  of  the  stone  is  but  little  used  notwithstanding 
that  its  broad  surface  appears  so  suitable  for  the  purpose,  but 
which  is  certainly  not  the  case,  in  the  first  place  the  spindle 
would  be  found  to  be  in  the  way  of  large  tools  or  their  handles, 
and  secondly,  the  constant  reduction  of  the  stone  arising  from 
the  friction  of  the  work  rubbing  away  its  granular  particles, 
would  soon  cause  the  flat  surface  to  degenerate  into  an  imperfect 
cone,  and  would  leave  a  lump  in  the  center,  or  if  the  stone  were 
kept  perfectly  flat,  it  would  be  at  the  expense  of  its  thickness, 
and  the  wedges  by  which  it  was  at  first  secured,  would  be 
gradually  exposed  and  loosened. 

The  stone  is  turned  either  to  or  from  the  operator  according 
to  circumstances,  and  in  all  practical  cases  it  is  best  that  it 
should  run  towards  the  extreme  edge  of  the  tool,  and  not  from 
it,  as  in  the  latter  case  the  last  portion  bends  away  from  the 
stone  and  leaves  a  film  or  wire  edge  upon  the  tool,  which  the 
reverse  direction  avoids.  The  edges  of  the  tools  should  be 
always  ground  parallel  to  the  axis  of  the  stone,  or  transversely, 
and  not  in  the  direction  of  their  length,  as  the  former  position 
makes  their  edges  concave  to  the  same  radius  as  the  stone,  and 
therefore  keener  and  better  prepared  for  the  action  of  the  oilstone. 

In  grinding  the  ends  of  rectilinear  tools  the  stone  should  run 
towards  the  operator,  as  in  turning,  and  for  their  sides  or  edges, 
it  is  perhaps  the  most  convenient  that  the  stone  should  travel 
the  reverse  way  or  backwards.  Pointed  tools  are  ground  much 
the  same  as  flat  tools,  but  the  choice  of  method  is  in  some 
respects  a  matter  of  personal  convenience. 

In  grinding  the  bevils  and  edges  of  instruments  in  their  manu- 
facture, the  workman  is  seated  on  a  board  called  the  horse,  and 
generally  rests  his  elbows  on  his  knees  for  steadiness,  as  explained 
on  page  1106.  The  work  is  mostly  applied  to  the  stone  by  the  hands 
alone  without  the  employment  except  in  rare  cases  of  any  guide 
beyond  the  sense  of  touch,  which  some  of  these  workmen  possess 
very  acutely,  and  the  amateur  will  find  it  desirable  and  sometimes 


GENERAL    REMARKS    ON    GRINDING    TOOLS.  1136 

imperative  to  trust  to  the  feel  alone  in  holding  the  tool  upon  the 
grindstone. 

To  grind  the  various  tools  with  an  uniform  bevil  requires  con- 
'siderable  practice,  as  of  course  the  least  variation  or  tremor  of 
the  hand  makes  a  corresponding  irregularity  in  the  bevil,  after  a 
time  however  the  fingers  acquire  considerable  sensibility  and 
readily  appreciate  when  the  tool  lies  fair  and  flat  upon  the  stone. 
In  some  cases  even  the  practical  men  apply  the  tools  upon  a 
guide  block  that  bears  the  same  relation  to  the  periphery  that 
should  exist  between  the  respective  edges  of  the  tools,  that  is,  if 
the  edge  of  a  tool  is  required  to  be  exactly  at  right  angles  to  the 
broad  surface  of  the  same,  the  guide  upon  which  it  is  applied 
should  point  directly  to  the  axis  of  the  stone,  or  be  as  a  radius. 
If  the  tool  should  differ  10  or  20  degrees  from  the  right  angle, 
the  rest  is  inclined  upwards  or  downwards  to  the  same  angle. 
There  are  also  instruments  in  which  the  rectilinear  tool  is 
grasped,  so  that  the  end  to  be  ground  forms  with  the  two  legs  of 
the  instrument  a  triangular  base,  the  feet  are  applied  to  some 
fixed  plane  surface,  and  the  tool  or  the  third  leg  rests  upon  the 
grinding  surface.  These  instruments  will  be  described  in 
Section  III. 

The  broad  flat  surfaces  of  tools  are  traversed  quickly  to  and 
fro  upon  the  top  of  the  grindstone,  as  a  short  period  of  rest 
would  grind  a  hollow  place  of  the  same  curvature  as  the  edge  of 
the  stone,  and  it  is  to  lessen  this  evil  as  far  as  possible  that  the 
largest  stones  are  employed  for  saws,  the  sides  of  which  are 
required  to  be  flat  and  parallel.  In  the  razor  on  the  other  hand 
the  curvature  is  desirable,  and  the  four  inch  stone  is  there  the 
nominal  desideratum,  still  smaller  grindstones  are  very  often 
employed. 

The  following  examples  of  the  mode  of  grinding  a  few  of  the 
most  usual  tools  for  wood  and  metal,  will  explain  the  methods 
pursued  by  artizans  generally  for  grinding  the  edges  of  their 
tools ;  and  which  differ  from  the  practices  of  the  cutler,  and 
grinder,  only  so  far  as  is  called  for  by  the  nature  of  their  respec- 
tive apparatus. 

In  grinding  an  ordinary  plane  iron  the  stone  travels  towards 
the  operator,  and  the  tool  is  applied  about  half  way  up  the  stone 
from  the  axis,  the  rest  is  not  generally  used,  but  the  iron  is 


1137  GRINDING    PLANE    IRONS. 


1 


grasped  firmly  in  the  right  hand  to  guide  the  tool,  the  position 
of  the  hand  being  the  same  as  that  for  sharpening  the  tool 
explained  in  page  1144  while  the  pressure  is  principally  given 
with  the  fingers  of  the  left  hand  applied  near  the  edge  of  the 
tool.  The  iron  is  inclined  vertically  so  that  the  chamfer  may  be 
ground  to  the  angle  of  about  25  degrees  with  the  face  of  the 
blade,  but  horizontally  the  iron  should  be  held  quite  square  to 
the  face  of  the  stone,  or  parallel  with  its  axis,  in  order  to  pre- 
vent either  corner  being  reduced  below  the  proper  line.  To 
assist  the  inexperienced  in  determining  when  the  plane  iron  is 
held  square,  the  top  iron  is  sometimes  kept  on  during  the  grind- 
ing, but  it  is  set  back  about  one  eighth  of  an  inch  from  the  edge, 
so  as  to  be  quite  out  of  the  reach  of  the  grindstone,  as  the  action 
of  the  top  iron  would  be  materially  injured,  or  altogether  spoiled, 
if  its  form  were  interfered  with,  it  is  however  a  safer  and  more 
cleanly  method  to  remove  the  top  iron  before  grinding. 

To  assist  in  keeping  the  arms  steady,  they  are  pressed  firmly 
to  the  sides  of  the  body  as  far  as  the  elbows ;  and  to  traverse  the 
tool  across  the  face  of  the  stone,  the  workman  swings  bodily  from 
side  to  side  without  moving  his  foot,  so  as  to  shift  the  tool 
gradually,  and  almost  constantly,  without  disturbing  the  position 
of  the  arms,  which  would  be  liable  to  grind  a  second  facet  upon 
the  bevil  of  the  tool,  or  otherwise  to  grind  the  edge  rounding 
instead  of  in  a  right  line.  The  grinding  should  be  continued 
until  nearly  the  whole  of  the  bevil  made  in  the  sharpening  on  the 
oilstone  has  been  removed,  but  unless  the  iron  be  notched,  it  is 
advisable  to  avoid  grinding  it  to  an  absolute  edge,  which  would  be 
liable  to  produce  a  wiry  film,  the  removal  of  which  is  troublesome. 

To  ensure  the  bevel  being  ground  flat,  it  is  in  all  cases  neces- 
sary that  the  tool  should  be  held  at  the  same  angle  throughout^ 
and  also  that  the  edge  of  the  tool  should  be  applied  at  the  same 
height  above  the  axis  of  the  grindstone.  Should  the  edge  of  the 
tool  be  shifted  upwards  a  little  during  the  grinding,  a  second 
facet  would  be  ground  somewhat  more  acutely,  and  if  shifted 
downwards  another  facet  somewhat  more  obtusely;  the  combina- 
tion of  the  two  movements  would  produce  a  rounded  instead  of 
a  flat  chamfer,  whereas  if  the  tool  be  held  quite  steady,  the 
chamfer  will  be  ground  slightly  concave,  from  the  circular  form 
of  the  stone,  and  which  is  desirable  in  tools  for  wood,  as  they 
then  cut  more  keenly. 


GRINDING    CHISELS,    GOUGES,    ETC.  1138 

Carpenters'1  chisels  are  ground  in  exactly  the  same  manner  as 
plane  irons,  but  chisels  below  about  half  an  inch  wide  are  more 
difficult  to  grind  square,  as  the  oblique  position  of  the  tool  in 
plan,  is  not  so  readily  detected  in  narrow  chisels. 

Carpenters1  gouges  are  ground  in  the  same  manner  as  chisels, 
except  that  while  the  fingers  of  the  left  hand  are  held  quite 
steady  to  give  the  requisite  pressure,  the  tool  is  rotated  in  the 
right  hand,  backwards  and  forwards,  in  an  arc  of  about  one  third 
of  a  circle,  much  the  same  as  in  boring  a  hole  with  a  bradawl. 
Gouges  that  are  sharpened  from  the  inside  do  not  admit  of 
being  ground  on  a  flat  stone,  they  are  therefore  in  general 
thinned  with  a  slip  of  gritstone  in  the  same  manner  as  the 
moulding  plane  irons  explained  in  the  next  paragraph. 

Moulding  plane  irons  are  not  generally  ground  because  from 
their  complicated  forms  they  would  require  grindstones  fashioned 
expressly  to  suit  nearly  every  kind,  but  preparatory  to  sharp- 
ening with  the  oilstone  slip,  the  bulk  of  the  material  is  removed 
either  with  files,  or  narrow  slips  of  gritstone  applied  in  much  the 
same  manner  as  the  file.  The  irons  of  moulding  planes  like 
those  of  ordinary  planes  are  always  made  principally  of  iron, 
with  a  thin  facing  of  steel  to  constitute  the  cutting  edge,  the  file 
may  therefore  be  successfully  applied  to  remove  the  bulk  of  the 
iron,  leaving  little  more  than  the  thin  steel  edge  to  be  abraded 
by  the  oilstone  slip.  As  mentioned  at  page  493  of  Vol.  II.  care 
is  required  in  restoring  the  edges  of  moulding  plane  irons  to 
keep  the  figure  of  the  cutter  in  the  proper  position  to  fifc 
the  plane.  Concave  plane  irons  may  be  successfully  ground  on 
the  conical  grinders  employed  for  concave  turning  tools,  and 
explained  in  the  fourth  section  of  this  chapter. 

The  soft  wood  turning  chisel  is  ground  with  two  bevils 
j  meeting  at  an  angle  of  from  25  to  40  degrees  as  explained  on 
page  513  of  Vol.  II.  and  as  there  shown  the  edge  is  placed 
oblique  at  an  angle  of  about  25  degrees.  In  grinding  this  chisel 
the  stone  should  revolve  towards  the  edge  of  the  tool,  the  rest  is 
not  generally  employed,  but  for  the  one  bevil  the  handle  is 
grasped  with  the  right  hand,  whilst  the  pressure  is  applied  with 
the  fingers  of  the  left,  much  the  same  as  in  grinding  the  plane 
iron ;  but  the  shaft  of  the  chisel  must  be  held  at  an  angle  in 
order  to  place  the  edge  square  upon  the  grindstone.  When  the 
chisel  is  turned  over  to  grind  the  second  bevil,  of  course  the 


VOL.  III. 


1139  GRINDING    TURNING    TOOLS. 

angle  at  which  the  shaft  is  held  must  be  reversed,  and  also  t 
position  of  the  hands,  the  left  then  grasping  the  handle  and  the 
right  supplying  the  pressure.  As  in  the  plane  iron  it  is  desirable 
not  to  grind  the  tool  quite  to  an  edge,  but  to  leave  a  narrow  line 
of  the  facet  produced  in  sharpening. 

In  grinding  a  turning  gouge,  which  requires  to  have  an  elliptical 
edge  as  noticed  on  page  512  Vol.  II.  the  stone  generally  travels 
from  the  operator.  The  tool  is  held  much  the  same  as  a  turning 
chisel,  except  that  the  oblique  position  of  the  shaft  is  uncalled 
for,  and  to  give  the  elliptical  form  to  the  edge,  the  gouge  is 
twisted  in  the  hand  half  a  turn  backwards  and  forwards ;  and  it 
is  at  the  same  time  traversed  across  the  face  of  the  stone,  not  in 
a  straight  line  against  the  rest,  as  for  most  rectilinear  tools,  but 
out  of  contact  with  the  support,  and  in  a  semicircular  path  like 
an  inverted  arch,  the  sides  of  the  gouge  being  applied  nearer  to 
the  top  of  the  stone  than  the  middle  of  the  gouge ;  a  few  trials 
will  render  this  action  familiar. 

Flat  tools  for  turning  hard  wood,  ivory,  and  steel,  are  ground 
with  the  stone  running  towards  the  operator,  and  the  tool  is 
applied  face  upwards  on  the  rest,  and  inclined  vertically  to  the 
suitable  angle  for  the  edge,  which  is  generally  from  60  to  80 
degrees,  but  flat  tools  and  chisels  must  be  held  square  horizon- 
tally to  avoid  producing  oblique  edges.  The  handle  of  the  tool 
is  grasped  in  the  right  hand  whilst  the  fingers  of  the  left 
applied  near  the  edge  serve  to  steady  the  tool,  which  is  gradually 
traversed  across  the  face  of  the  stone,  but  to  keep  the  edge 
straight  care  must  be  taken  that  both  hands  are  moved  equally, 
or  parallel  with  the  axis  of  the  stone,  otherwise  the  edge  of  the 
tool  will  become  rounded. 

Flat  tools  for  brass  are  ground  in  the  same  manner  as  the 
above,  except  that  the  vertical  inclination  is  not  required,  and 
the  tool  is  pointed  to  the  axis  of  the  stone  as  in  turning  a 
cylinder. 

Right  and  left  side  tools  are  most  conveniently  ground  with 
the  stone  running  backwards,  and  the  tool  is  applied  at  the  top 
of  the  stone,  with  its  face  or  upper  surface  towards  the  operator, 
and  its  shaft  parallel  with  the  axis  of  the  stone,  the  tool  being 
inclined  backwards  in  order  to  give  the  required  bevil.  For 
grinding  the  end,  the  stone  travels  forwards  as  usual,  and 
tool  is  applied  on  the  rest  as  in  grinding  a  flat  tool. 


GRINDING    TURNING    TOOLS.  1140 

Triangular  tools  that  are  required  to  cut  very  keenly,  are 
ground  in  the  same  manner  as  the  side  tools,  and  by  which  the 
edges  are  made  slightly  concave ;  but  when  the  triangular  tool  is 
required  to  be  less  penetrative  and  more  durable,  it  is  applied 
on  the  top  of  the  stone,  at  right  angles  to  its  axis,  and  traversed 
quickly  backwards  and  forwards  as  in  grinding  a  flat  surface. 

Square  tools  for  turning  brass  are  ground  in  the  same  manner 
as  triangular  tools. 

A  graver  is  held  point  upwards  on  the  rest,  with  the  stone 
running  towards  the  operator,  and  it  is  best  to  remove  the 
extreme  point  by  grinding  a  minute  triangular  facet,  at  right 
angles  to  the  principal  chamfer,  but  less  in  size  than  a  pin's 
head,  the  tool  performs  as  well,  and  the  point  is  considerably 
strengthened ;  it  requires  only  a  touch  on  the  stone.  Many  of 
the  tools  for  metal  are  used  at  once  from  the  grindstone,  which 
could  not  be  the  case  if  a  film  were  left  upon  them,  as  explained 
|  at  page  1135. 

Point  tools  are  ground  in  the  same  manner  as  flat  tools, 
i  except  that  the  tool  is  held  horizontally  at  the  suitable  angles 
I  for  the  point. 

Large  pointed  drills  that  cut  in  the  one  direction  only  are 
i  ground  the  same  as  point  tools,  except  that  for  the  second  edge 
the  drill  is  turned  over  and  applied  at  the  same  angle  as  for  'the 
first  edge. 

Small  pointed  drills  that  cut  in  both  directions  are  generally 
sharpened  on  the  oilstone  without  grinding.  When  the  latter 
process  is  resorted  to,  however,  the  tool  is  held  like  a  pen  near 
the  top  of  the  stone,  which  runs  backwards. 

Round  tools  are  held  upon  the  rest  much  the  same  as  flat 
tools,  except  that  they  are  not  traversed  in  a  line  across  the 
stone,  but  while  the  extremity  of  the  tool  is  kept  nearly 
stationary,  the  handle  is  moved  horizontally  through  a  semi- 
circle around  the  part  of  the  tool  supported  on  the  rest,  and 
which  serves  as  the  imaginary  axis. 

Round  tools  that  are  much  bevilled  are  sometimes  ground  in 
!  a  manner  similar  to  the  gouge,  but  without  the  rotation  on  the 
axis  of  the  tool  therein  called  for. 

Heel  tools  for  turning  iron  are  supported  upon  the  rest 
exactly  in  the  position  for  turning,  shown  in  figs.  415  and  417, 
page  525,  Vol.  II.,  but  the  handle  is  a  little  more  depressed,  to 

i  2 


1141  SHARPENING    CUTTING    TOOLS    ON    THE   OILSTONE. 

place  the  bevil  at  the  suitable  angle,  and  the  tool  is  swept 
round  in  a  semicircle  like  the  round  tools,  the  point  of  the  heel 
serving  as  the  axis  of  rotation. 

Slide  rest  tools  for  metal  turning  are  generally  held  upon  the 
rest,  and  as  they  are  mostly  used  direct  from  the  grindstone 
without  having  recourse  to  the  oilstone,  it  is  desirable  in  al 
possible  cases  that  the  stone  should  run  towards  the  edge 
They  are  applied  to  the  grindstone  after  the  same  genera 
method  as  the  hand  tools  of  corresponding  forms,  but  as 
explained  in  pages  530  to  534  of  Vol.  II.,  the  fixed  tools 
require  additional  care  to  preserve  the  proper  angles  for  cutting 
and  the  tool-gage,  figs.  438  and  439,  may  with  advantage  b( 
resorted  to  for  determining  the  proper  forms. 

Detached  cutters  for  fitting  into  cutter  bars,  such  as  those 
shown  in  figs.  440  to  442,  page  535,  Vol.  II.,  are  too  small  to 
be  held  in  the  fingers,  they  are  therefore  fixed  in  socket  handles 
of  appropriate  forms,  or  otherwise  they  are  grasped  in  a  hand- 
vice,  which  serves  as  the  temporary  handle  for  applying  them  to 
the  grindstone. 

Screw  tools  and  moulding  tools  used  by  hand,  that  are  cut  to 
their  respective  forms  on  steel  hobs  or  cutters,  as  explained  on 
page  591,  Vol.  II.,  are  sharpened  only  upon  their  upper  surfaces, 
as  the  forms  of  the  tools  would  be  impaired  by  grinding  their 
ends.  They  are  frequently  sloped  off  on  the  face,  and  this  method 
serves  sufficiently  well  for  tools  applied  to  the  hardwoods  and 
ivory,  but  as  explained  on  page  520,  Vol.  II.,  the  slope  increases 
the  angle  of  the  edge  ;  and  the  method  of  nicking  in  the  tools, 
shown  in  fig.  407,  by  applying  them  transversely  on  the 
grindstone,  is  far  preferable  for  screw  tools  intended  for  iron 
and  steel. 

SECT.  II. SHARPENING    CUTTING    TOOLS    ON    THE    OILSTONE. 

THE  completion  of  the  edges  of  tools  after  grinding  is  effected 
either  upon  the  Turkey  oilstone  or  one  of  the  family  of  hone 
slates  described  on  page  1065.  These  stones  differ  exceedingly 
in  quality,  some  being  so  hard  as  scarcely  to  take  any  hold 
of  the  tool,  whilst  others  are  altogether  as  soft.  The  latter  are 
best  for  broad  tools,  as  they  cut  rapidly,  and  are  then  less 
exposed  to  being  irregularly  worn  than  when  used  for  narrow 
tools. 


ANGLES   AT    WHICH    TOOLS    ARE    SHARPENED.  1142 

On  the  whole,  the  preference  is  given  to  the  Turkey  oilstone 
for  ordinary  tools,  and  the  yellow  German  hone  for  razors  and 
delicate  instruments.  The  Turkey  stone  being  crystalline,  is  cut 
into  square  blocks  with  the  slicer,  fed  with  diamond  powder; 
but  the  hone  slates  may  be  split  through  their  natural  fissures 
into  rough  parallel  blocks ;  and  before  use  they  are  ground  flat 
by  rubbing  them  on  a  wide  stone,  or  iron  plate,  fed  with  hard 
sand  or  emery.  The  stones  are  afterwards  mounted  in  a  wooden 
stock,  as  explained  on  page  1081. 

In  sharpening,  as  in  the  majority  of  mechanical  operations, 
the  work  becomes  a  copy  of  the  tool,  and  a  flat  oilstone,  now 
the  tool,  will  produce  the  most  correct  edge  with  the  least 
expenditure  of  time.  The  oilstone  should  be  kept  flat  princi- 
pally by  an  even  distribution  of  the  wear;  the  stone  or  iron 
plate  must,  however,  be  occasionally  resorted  to  for  restoring  a 
level  surface. 

The  oilstone  should  be  moistened  with  good  clean  oil  not 
disposed  to  dry;  otherwise  it  becomes  thick,  like  glue  or  varnish, 
and  entirely  prevents  the  action  of  the  stone  upon  the  tool. 
Soap  and  water  have  been  recommended  for  razor  hones,  but  its 
rapid  evaporation  is  unfavourable  to  its  use. 

The  angles  at  which  the  tools  are  sharpened  for  different 
materials  have  been  already  treated  of  in  the  preceding  volume. 
It  is  there  mentioned  that  the  ultimate  angles  of  the  ordinary 
tools  for  wood  vary  from  about  25  to  45  degrees,  according  to 
the  hardness  of  the  wood  ;  and  the  manner  in  which  the  tool  is 
applied.  The  smallest  angle,  or  about  25  degrees,  is  used  for 
the  spokeshave  iron.  Paring  chisels  and  gouges  are  generally 
sharpened  at  about  30  degrees,  and  plane  irons  at  about 
35  degrees.  Turning  chisels  and  gouges  vary  from  about  30  to 
45  degrees.  The  screw  tools  and  moulding  tools  for  hardwood 
and  ivory  are  made  at  from  50  to  60  degrees.  Tools  for  iron 
and  steel  have  angles  of  from  60  to  70  degrees  ;  and  those  for 
brass  and  gun-metal  from  80  to  90  degrees. 

In  all  cases  in  which  the  sharpening  of  the  tools  is  completed 
upon  the  oilstone,  the  principal  part  of  the  material  is  removed 
upon  the  grindstone,  at  an  angle  a  little  less  than  that  forming 
the  ultimate  edge  of  the  tool,  the  greatest  differences  being 
made  in  the  tools  for  soft  wood,  which  only  require  a  moderate 
degree  of  strength  in  their  edges,  such  as  the  plane  irons,  paring 


1143  GENERAL    REMARKS    ON    SHARPENING    TOOLS. 

chisels,  and  gouges,  which  are  generally  ground  about  10  degrees 
more  acutely  than  they  are  sharpened.  In  the  tools  for  metal, 
which  require  considerable  strength  in  their  edges,  the  differ- 
ence is  not  more  than  about  2  degrees.  It  is  therefore  neces- 
sary in  all  cases  that  the  shaft  of  the  tool  to  be  sharpened, 
should  be  held  at  such  an  angle  to  the  surface  of  the  oilstone,  as 
to  place  the  edge  of  the  tool  at  the  required  angle.  Thus,  if  a 
tool  with  one  bevil  only,  such  as  a  plane  iron,  is  to  be  sharpened 
at  an  angle  of  40  degrees,  the  shaft  of  the  tool  is  held  at  an 
angle  of  40  to  the  face  of  the  oilstone ;  but  if  a  tool  with  two 
bevils,  such  as  a  turning  chisel,  is  to  be  sharpened  at  an  angle  of 
40,  its  shaft  must  be  held  at  half  that  angle,  or  20  degrees,  so  as 
to  place  the  second  bevil  at  the  angle  of  40.  It  consequently 
results,  from  the  tools  being  placed  at  two  different  angles  on 
the  grindstone  and  oilstone  respectively,  that  the  chamfer  of  the 
tool  presents  two  bevils,  the  one  produced  by  the  grindstone,  the 
other  by  the  oilstone,  and  which,  in  the  case  of  the  tools  for  soft 
wood,  are  quite  distinct,  but  in  the  tools  for  metal  gradually 
slide  into  each  other. 

It  has  been  explained  at  page  1137,  that  some  practice  is 
required  to  enable  the  tools  to  be  held  steadily  upon  the  grind- 
stone at  the  proper  angle,  the  same  remarks  apply  to  setting 
tools  upon  the  oilstone  ;  but  in  the  latter  case  the  difficulty  is 
increased  by  the  necessity  for  rubbing  the  tools  backwards  and 
forwards  upon  the  quiescent  stone.  With  a  little  care  and  practice, 
however,  the  hands  acquire  the  habit  of  traversing  the  tool  at 
the  same  angle  in  parallel  lines,  and  which  is  quite  essential,  as 
should  a  rocking  motion  be  given  to  the  tool  in  the  direction  of 
the  bevil,  during  the  stroke,  the  chamfers,  instead  of  being  flat, 
would  become  rounded,  and  the  ultimate  edge  of  the  tool  would 
be  thereby  thickened  and  unsuited  for  its  purpose. 

Rectilinear  tools  that  are  sharpened  upon  the  one  bevil  only, 
require  to  be  laid  flat  on  the  face  to  remove  the  wire  edge  ;  this 
is  done  as  the  last  process  of  setting  ;  the  tool  should  be  rubbed 
upon  the  face  no  more  than  is  absolutely  necessary,  and  not  in 
the  least  degree  tilted  up,  which  would  produce  a  second  bevil,  and 
greatly  increase  the  angle  of  the  edge,  at  the  same  time  destroy- 
ing the  accuracy  of  the  face  given  in  the  manufacture  of  the  tool. 


SHARPENING    CABINET- MAKERS*    TOOLS.  1144 

The  method  of  sharpening  a  plane  iron  has  been  described 
somewhat  in  detail  at  page  496,  Vol.  II.,  the  peculiar  mode  of 
holding  the  plane  iron  is  there  stated  as  follows  : — "  The  iron  is 
first  grasped  in  the  right  hand,  with  the  fore  finger  only  above 
and  near  the  side  of  the  iron,  and  with  the  thumb  below ;  the 
left  hand  is  then  applied  with  the  left  thumb  lapping  over  the 
right,  and  the  whole  of  the  fingers  of  that  hand  on  the  surface  of 
the  iron ;  the  edge  should  be  kept  nearly  square  across  the  oil- 
stone, as  when  one  corner  precedes  the  other,  the  foremost  angle 
is  the  more  worn."  This  method  of  holding  the  tool  gives  great 
steadiness  and  command  of  position,  and  it  should  be  adopted 
with  all  rectilinear  tools  that  will  admit  of  its  application ;  as  the 
back  of  the  tool  is  then  firmly  supported  upon  the  three  fingers 
of  the  right  hand,  assisted  by  the.  two  thumbs  placed  beneath, 
while  the  pressure  is  given  almost  exclusively  by  the  fingers  on 
the  top  of  the  blade. 

Narrow  chisels  that  are  too  small  to  be  grasped  in  both  hands, 
are  held  in  the  right  hand  much  the  same  as  a  plane  iron,  and 
the  pressure  is  principally  given  by  the  first  two  fingers  of  the 
left  applied  near  the  edge  of  the  tool,  and  over  the  forefinger  of 
the  right  hand. 

Chisels  that  are  required  for  paring  across  the  end  grain  of 
moderately  soft  wood,  are  considered  to  hang  better  to  the  work 
when  they  have  a  very  slight  keen  burr  or  wire  edge,  thrown  up 
on  the  face  of  the  tool ;  to  produce  this  they  are  sharpened  quite 
smoothly  as  usual,  but  for  the  last  finish  the  bevil  is  passed  once 
or  twice  over  the  stone  as  in  sharpening,  and  which  raises  a 
minute  wire  edge  sufficient  for  the  purpose. 

Cabinet-makers1  gouges  that  are  sharpened  externally,  and 
are  required  to  have  the  edge  square  across  the  end  of  the  tool, 
are  held  in  the  right  hand  the  same  as  small  chisels,  and  traversed 
straight  along  the  oilstone  with  the  shaft  at  right  angles  to  the 
side  of  the  stone ;  the  first  two  fingers  of  the  left  hand  are 
applied  within  the  concavity  of  the  gouge,  and  serve  as  a  fulcrum 
upon  which  the  tool  is  twisted  about  one-fourth  of  a  turn,  with 
each  stroke  backwards  and  forwards  upon  the  oilstone,  so  as  to 
subject  all  parts  of  the  chamfer  equally  to  the  action  of  the  stone; 
this  is  continued  until  the  edge  has  been  uniformly  sharpened. 
The  flat  oilstone  cannot  be  applied  to  remove  the  wire  edge  from 
the  concave  side  of  the  tool,  but  which  is  effected  with  a  slip  of 


1145  SHARPENING  TURNING  TOOLS. 


oilstone  having  a  convex  edge,  as  described  on  page  1081,  the 
gouge  is  held  in  the  left  hand  whilst  the  oilstone  slip  is  rubbed 
up  and  down  the  inside  of  the  gouge  with  the  right  hand,  care 
being  taken  to  keep  the  slip  flat  on  the  face  of  the  tool  to  avoid 
making  a  second  chamfer ;  at  the  last  finish  the  side  of  the  slip 
is  generally  swept  once  or  twice  around  the  outside  of  the  edge. 

Gouges  that  are  sharpened  from  the  inside  must  be  set  entirely 
with  the  oilstone  slip,  but  the  gouge  is  in  this  case  generally 
rested  against  the  bench,  and  the  process  is  more  tedious. 

It  is  at  all  times  rather  difficult  to  keep  the  curved  edge  of 
the  gouge  level  across  the  end.  When  the  edge  has  become 
irregular  from  repeated  sharpening,  it  is  restored  by  placing  the 
gouge  perpendicular  upon  the  oilstone,  and  reducing  the  end  to 
a  level  surface ;  after  which  the  edge  is  sharpened  as  above 
described. 

Moulding  plane  irons  are  held  in  the  left  hand  face  upwards, 
that  the  operator  may  the  more  exactly  see  the  part  to  which 
the  oilstone  slip  is  applied ;  the  straight  portions  of  the  edge  are 
sharpened  upon  the  ordinary  oilstone,  and  to  remove  the  wire 
edge  the  iron  is  laid  flat  on  the  oilstone  in  the  same  manner  as 
a  chisel. 

The  turning  chisel  for  soft  wood,  is  sharpened  in  the  same 
manner  as  the  paring  chisel,  the  only  differences  arising  from  the 
double  chamfer  and  the  oblique  edge  ;  the  extreme  point  of  the 
turning  chisel  requires  to  be  made  quite  keen,  that  it  may  be 
used  for  turning  flat  surfaces. 

The  turning  gouge,  when  sharpened  upon  the  flat  oilstone, 
held  in  the  same  manner  as  the  cabinet-maker's  gouge,  but  tc 
sharpen  its  elliptical  edge,  the  tool  is  traversed  in  a  concave 
sweep  upon  the  face  of  the  oilstone,  whilst  the  gouge  is  twisted 
in  the  hand  exactly  as  described  for  grinding  this  tool.  Some- 
times both  the  outside  and  inside  of  the  turning  gouge  are  set  with 
the  oilstone  slip ;  in  this  case  the  gouge  is  held  in  the  left  hand, 
and  rested  against  the  popit  head,  or  any  convenient  part  of 
the  lathe,  whilst  the  flat  surface  of  the  oilstone  slip  is  rubbed 
lengthways  upon  the  chamfer  of  the  tool  around  each  part,  and 
then  the  round  edge  of  the  slip  is  rubbed  within  the  concave  flute. 

The  wire  edge  left  by  the  grindstone  upon  the  gouge  must  be 
entirely  removed  before  the  tool  is  fit  for  use,  it  is  expedited  by 
drawing  the  chamfer  of  the  tool  through  a  notch  cut  by  itself  in 


SETTING    RAZORS.  1146 

21  piece  of  wood  as  hard  as  beech,  a  few  touches  of  the  oilstone 
slip  will  then  render  the  edge  perfectly  keen  and  fit  for  use. 

Tools  for  turning  hardwood,  ivory,  and  those  for  finishing  the 
metals,  are  sharpened  upon  the  oilstone  much  the  same  as  the 
corresponding  tools  for  soft  wood,  the  principal  difference  being 
that  they  are  held  upon  the  stone  at  a  greater  angle,  according 
to  the  material  upon  which  they  are  to  be  employed  ;  the  appro- 
priate angles  and  forms  for  the  various  materials  have  been  fully 
explained  in  the  second  volume  of  this  work.  Tools  for  steel  cut 
the  most  keenly  and  smoothly  when  left  from  a  fine  grindstone. 
Tools  for  iron  cut  rather  more  smoothly  when  finished  on  the 
oilstone,  but  the  edge  is  not  so  enduring,  and  therefore  with 
tools  for  iron  the  oilstone  is  only  occasionally  resorted  to  for 
giving  a  smooth  edge  for  the  last  finish  of  the  work.  Tools  for 
brass  and  gun-metal,  when  left  from  the  grindstone,  cut  too 
rankly,  and  are  said  by  workmen  to  drag ;  they  are  therefore 
always  sharpened  upon  the  oilstone,  and  the  finishing  tools  for 
brass  and  gun-metal  are  frequently  burnished,  as  mentioned  at 
page  522  of  the  second  volume ;  in  this  case  the  burnisher  is 
placed  at  right  angles  to  the  face  of  the  tool,  and  passed  once, 
or  at  most  twice,  across  the  edge  with  moderate  pressure. 

Finishing  tools  for  soft  wood  are  sometimes  burnished  with 
the  back  of  the  turning  gouge,  applied  at  an  angle  to  throw  up  a 
wire  edge  which  is  used  with  a  scraping  action.  The  broads 
figs.  372  and  373,  page  515,  Vol.  II.,  are  thus  employed  for  flat 
surfaces.  Right  side  tools,  fig.  382,  ground  at  an  angle  of  about 
30  degrees,  and  burnished,  serve  for  the  interior  of  boxes,  and 
ordinary  paring  chisels  are  used  in  like  manner  for  finishing 
cylindrical  and  convex  works.  The  method  of  sharpening  the 
joiner's  scraper  with  the  burnisher  is  explained  at  page  484, 
Vol.  II. 

SECT    III. SETTING    RAZORS. 

PERHAPS  of  all  cutting  instruments,  the  razor  possesses  the 
most  general  and  personal  interest,  in  respect  to  the  conditions 
required  for  its  perfect  action,  and  it  is  therefore  proposed  to 
notice  at  moderate  length  the  principal  circumstances  on  which 
the  perfection  of  its  edge  depends. 

The  razor  notwithstanding  the  peculiarity  of  its  outline,  con- 
forms strictly  to  the  ordinary  wedge  form  section  of  most  cutting 


1147  PROPORTIONS  OF  RAZORS. 

tools,  but  as  it  requires  the  most  delicate  edge  that  can  be  pi 
duced,  it  is  so  formed  as  to  facilitate  to  the  utmost  the  process 
of  sharpening.  For  instance  in  the  plane  iron,  chisel,  penknife, 
lancet,  and  most  other  instruments,  the  angles  of  the  one  or  both 
the  sides  of  the  wedge  or  cutting  edge  are  determined  by  the 
particular  inclination  at  which  the  tool  is  held  upon  the  stone, 
but  if  the  hand  wavers,  the  setting  or  facet  instead  of  becoming 
a  plain  flat  surface,  becomes  rounded  and  ill  defined. 

In  the  razor  on  the  other  hand  the  proportion  between  the 
width  of  the  blade,  and  the  thickness  of  the  back,  is  almost 
always  such  that  when  the  blade  is  laid  perfectly  flat  on  the 
hone,  or  so  that  the  edge  and  back  both  touch,  the  suitable  angle 
is  obtained,  and  which  varies  from  about  17  to  20  degrees ;  the 
exact  measure  of  the  angle  is  very  little  studied,  although  in 
reference  to  the  principle  of  cutting  tools  some  little  variation 
ought  to  be  made,  in  choosing  the  thickest  edge  for  the  strongest 
beard.  It  does  sometimes  happen  that  the  razor  is  not  laid 
quite  flat  on  the  hone,  but  that  it  is  slightly  tilted,  this  occurs 
when  a  wide  razor  that  has  been  ground  on  a  large  stone  is 
required  to  be  sharpened  for  a  stiff  beard ;  but  it  so  rarely  occurs 
that  the  razor  is  placed  otherwise  than  flat  on  the  hone,  that  the 
exception  may  be  overlooked. 

The  magnified  sections  of  razors  in  figs.  1031  to  1036,  which 
for  distinctness  are  drawn  three  times  their  full  size,  and  for 
comparison,  of  the  same  angle  or  18  degrees  throughout,  exhibit 
various  modes  adopted  to  avoid  the  necessity  for  sharpening  the 
entire  side  of  the  imaginary  wedge,  represented  by  the  dotted 
lines,  by  hollowing  the  sides  in  different  ways.  It  is  apparent 
that  it  would  be  much  more  tedious  and  difficult  to  wear  down 
the  imaginary  flat  sides  represented  by  the  dotted  lines,  than  the 
small  portion  of  the  same  which  are  supposed  to  remain ;  and 
indeed  the  entire  dotted  line  if  sharpened,  would  most  probably 
become  rounded  instead  of  flat.  The  concavity  therefore  facili- 
tates the  placing  of  the  razor  on  the  hone,  it  thins  the  edge 
leaving  but  little  for  the  stone  to  abrade,  and  it  prevents  the 
finished  appearance  given  to  the  sides  of  the  razor  being 
detracted  from  by  the  sharpening. 

Figs.  1031  and  1032,  represent  the  section  of  that  description 
of  razor  blade  which  is  by  far  in  the  most  common  use,  as  before 
observed  the  widths  of  the  blade  and  the  thicknesses  of  their 


SECTIONS    OF    RAZORS. 


1148 


backs  are  such  as  to  give  in  each  an  ultimate  edge  of  18  degrees 
when  the  blade  is  sharpened  on  the  hone,  but  fig.  1 032,  is  ground 


FIGS.  1031. 


FIGS.  1034. 


1032. 


1035. 


1033. 


1036. 


transversely  on  a  wheel  of  four  inches  diamater,  and  fig.  1031, 
on  one  of  twelve  inches,  the  general  extremes  of  curvature.  It 
is  clear  that  the  former  possesses  an  edge  that  is  thinner  and 


1149  VARIOUS    MODES    IN    WHICH    RAZORS    ARE    GROUND. 

more  flexible,  and  that  presents  a  narrower  edge  or  plane  to  be 
abraded  by  the  hone  ;  and  which  latter  in  consequence  will  cut 
with  greater  precision  and  delicacy  than  if  it  had  to  abrade  the 
entire  surface.  The  curvature  in  most  general  use  for  best 
razors  is  intermediate,  or  from  5  to  6  inches,  but  stones  of  from 
12  to  15  inches  diameter  are  from  motives  of  economy  resorted 
to  for  common  razor  blades. 

In  some  few  cases  the  edge  of  the  razor  is  ground  lengthways 
on  the  stone,  so  as  to  become  nicked  in,  in  the  manner  repre- 
sented in  fig.  1033,  and  in  this  way  any  degree  of  thinness  may 
be  given,  and  also  extended  throughout  any  desired  width.  This 
mode  of  grinding  the  razor  is  however  more  difficult,  and  the 
feebleness  of  the  edge  may  be  thereby  easily  carried  to  excess  ; 
and  from  the  vibration  to  which  they  are  liable  when  applied  to 
a  strong  beard,  they  are  called  by  the  Sheffield  cutlers,  rattler 
razors. 

Sometimes  the  two  methods  of  grinding  are  combined,  as 
shown  in  fig.  1034,  in  this  case  the  razor  is  first  ground  trans- 
versely as  for  fig.  1032,  and  it  is  subsequently  ground  lengthways 
so  as  to  be  nicked  in  for  about  half  its  width  ;  these  razors  are 
known  by  Sheffield  workmen  as  half  rattlers.  For  the  sake  of 
variety  the  longitudinal  grinding  is  sometimes  only  extended 
about  one  quarter  of  an  inch  from  the  edge. 

Other  razors  as  in  fig.  1035,  are  made  as  very  thin  acute  blades 
fixed  in  a  detached  back  somewhat  like  a  dovetail  saw,  in  this 
case  the  edges  of  the  blade  and  of  the  back  are  simultaneously 
whetted  on  the  hone ;  but  no  advantage  appears  to  result  from 
the  construction,  on  the  contrary  the  blade  cannot  be  reground 
without  removal  from  the  stock,  which  implies  the  risk  of  its 
being  reduced  below  the  edge  of  the  stock  so  as  to  prevent  its 
replacement. 

Fig.  1036  represents  another  of  the  modes  in  which  razors 
are  occasionally  constructed,  in  this  a  loose  frame  or  guard  of 
brass  is  added  to  the  blade.  The  idea  in  this  case  is  to  prevent 
the  liability  to  accident  incurred  by  nervous  or  infirm  persons 
from  the  tremor  of  their  hands.  The  frame  is  intended  to  act 
as  a  muzzle  or  guard  to  prevent  the  edge  penetrating  to  any 
serious  depth,  and  the  instrument  is  known  as  a  guard  razor. 


TESTS    FOR    KEENNESS    OF    RAZORS.  1150 

The  keenness  of  the  edge  of  the  razor  is  commonly  tried  by 
making  a  faint  incision  in  the  thick  skin  covering  the  inner  edge 
of  the  palm  of  the  left  hand,  but  the  cutler  also  tries  the  razor 
upon  the  thumb  or  finger  nail.  The  razor  is  either  placed  in  a 
line  with  the  finger  and  obliquely  across  the  end  of  the  nail,  or 
a  still  more  sensitive  test  is  to  place  the  blade  at  right  angles  to 
the  finger,  and  allow  it  to  rest  upon  the  back  of  the  nail,  that 
of  the  third  finger  being  by  some  considered  the  most  sensitive. 
In  this  manner  a  very  minute  notch  in  the  edge  is  quite  per- 
ceptible, and  the  keenness  may  also  be  appreciated  by  the  degree 
in  which  the  razor  hangs  to  the  nail,  as  the  keen  blade  will  make 
the  deeper  incision,  and  appear  to  offer  a  more  dragging  yet 
smooth  resistance,  whereas  the  blunt  razor  will  slide  over  with 
less  penetration  and  drag. 

A  more  scientific  method  was  proposed  by  Mr.  Kingsbury  in 
his  pamphlet  on  the  razor,  namely  the  examination  of  the  entire 
edge  with  a  magnifier,  and  which  process  when  applied  in  a 
sufficiently  powerful  degree  will  doubtless  exhibit  the  causes  why 
the  razor  fails  in  its  purpose,  and  which  are  sometimes  threefold, 
namely  first  the  razor  may  be  notched,  secondly  it  may  have  a 
loose  pliant  film  or  wiry  edge,  or  thirdly,  instead  of  a  keen  acute 
edge  it  may  be  blunt  and  obtuse,  which  is  generally  due  to  the 
excessive  use  of  the  razor  strop  ;  upon  each  of  these  considera- 
tions some  few  observations  will  be  offered. 

First,  notches  are  liable  to  occur  in  a  razor  from  the  blade 
having  been  overheated,  either  in  the  forging  or  hardening,  a 
fault  which  is  irretrievable,  as  it  renders  the  steel  permanently 
brittle,  and  altogether  incapable  of  receiving  a  fine  acute  edge, 
as  the  particles  of  the  metal  break  away  at  the  extreme  edge  on 
the  hone.  The  brittleness  may  occur  in  a  somewhat  less  degree, 
when  the  razor  without  having  been  overheated  is  simply  left  too 
hard,  so  as  to  require  to  be  let  down  or-  tempered  a  little  lower 
than  at  first. 

Secondly,  the  wire  edge  generally  occurs  from  the  hone  being 
too  much  used,  as  when  the  two  faces  of  the  wedge  are  riflbbed 
away  beyond  that  point  at  which  they  first  meet,  the  slender  film 
of  steel  commences  to  form,  because  the  extreme  edge  is  then  so 
thin  that  it  bends  away  from  the  hone  instead  of  being  rubbed 
off.  The  wire  edge  is  more  liable  to  occur  when  the  one  side  of 
the  blade  is  more  whetted  than  the  other,  and  if  it  be  obstinate 


1151  FAULTY  CONDITION  OF  RAZORS. 

in  its  resistance  to  removal,  it  frequently  indicates  further  that 
the  blade  is  too  soft,  as  if  the  razor  blade  be  made  too  hard, 
the  metal  will  be  brittle  instead  of  flexible,  and  the  thin  extre- 
mity break  off  instead  off  forming  the  filmy  edge. 

The  temper  of  the  blade  ought  to  be  such  as  to  be  indisposed 
to  become  either  permanently  notched  or  wiry  from  the  action  of 
the  hone.  But  in  the  application  of  the  various  grinding  and 
polishing  wheels,  especially  the  latter,  there  is  always  some  risk, 
as  the  temptation  to  expedite  the  work  causes  too  much  vigour 
to  be  occasionally  used,  thereby  giving  to  the  blade  so  much  heat 
as  to  reduce  its  temper;  an  error  the  unscrupulous  may  easily 
gloss  over,  by  touching  the  work  more  lightly,  and  thereby 
removing  the  colour,  or  that  index  whereby  the  temper  of 
the  instrument  is  commonly  estimated.  But  the  experienced 
cutler  is  generally  able  to  distinguish  by  the  feel  of  the  cut,  or  of 
the  action  of  his  own  particular  hone,  between  such  blades  as 
either  exceed  or  fall  short  of  the  appropriate  temper. 

Thirdly,  in  a  new  or  a  recently  ground  razor,  the  thick  obtuse 
edge  shows  that  the  blade  has  not  been  sufficiently  rubbed  on 
the  hone,  and  in  a  used  razor,  it  more  commonly  indicates  that 
partly  by  the  using  of  the  razor,  and  partly  by  its  being  inter- 


FIGS.  1037. 


mediately  stropped  to  renovate  the  edge,  it  has  been  too  much 
rounded;  so  that  instead  of  the  two  narrow  facets  constituting 
the  edge  being  plane  surfaces  and  meeting  at  from  17  to  20 
degrees  as  left  from  the  hone,  they  are  seen  to  have  become 
considerably  rounded,  so  as  probably  to  meet  at  more  than 
double  the  original  angle,  a  condition  explained  by  the  diagrams 
figs.  1037  and  1038,  in  which  for  perspicuity  the  extreme  edges 
are  shown  about  twenty  times  their  true  size.  This  fault  or  the 
rounded  edge  is  also  readily  detected  with  the  magnifier,  and  is 
almost  sure  to  occur  from  the  use  of  a  soft  strop,  as  the  leather 
immediately  against  the  edge  from  being  indented,  rises  as  an 
abrupt  angle  and  mutilates  the  keenness  of  the  blade.  If  how- 


WHETSTONES    EMPLOYED    FOR    SETTING   RAZORS.  1152 

ever  the  razor  at  any  of  its  stages  of  manufacture  or  setting 
have  been  treated  without  uniformity,  it  may  possess  at  different 
parts  of  its  edge  all  these  errors,  but  which  is  less  to  be  expected 
than  that  the  one  error  should  prevail. 

If  neither  of  the  above  three  faulty  conditions  are  discernible 
by  the  careful  use  of  a  lens  of  one  half  to  one  third  of  an  inch 
focus,  (or  of  a  linear  power  of  twenty  or  thirty,)  such  razor  will 
in  general  be  found  to  act  with  satisfaction,  but  the  keenest 
razor  when  delicately  examined  with  a  lens  of  one  fifth  to  one 
tenth  of  an  inch  focus,  (or  a  linear  power  of  fifty  to  one  hundred,) 
or  still  better  with  a  microscope  of  not  .less  than  equivalent 
power,  will  present  a  faintly  undulating  and  irregular  edge,  which 
resembles  rather  a  ripple  mark,  than  the  angular  teeth  of  the 
edge  of  the  saw,  to  which.it  is  usually  compared.  Indeed  the 
edge  of  a  razor  of  ordinary  quality,  bears  the  microscopic  exami- 
nation much  better  than  might  be  expected ;  but  as  no  surface 
polished  by  art  is  free  from  scratches,  it  must  happen  that  every 
such  scratch  when  continued  to  the  edge  formed  by  two  planes 
meeting  at  so  small  an  angle,  deprives  the  otherwise  continuous 
edge  of  a  small  portion  of  its  material,  and  thence  constitutes  a 
notch,  but  the  notches  are  the  smaller,  the  finer  the  abrading 
surface  used  in  producing  the  edge. 

When  however  the  errors  are  so  minute  as  to  require  to  be 
thus  magnified  some  fifty  or  one  hundred  times,  to  render  them 
visible,  they  are  too  minute  to  be  detected  by  the  skin,  the  nail, 
or  the  employment  of  the  instrument  on  the  beard.  Having 
explained  the  good  and  bad  condition  of  the  razor,  the  practice 
of  setting  the  instrument  will  be  now  the  more  easily  under- 
stood, and  it  is  proposed  first  to  describe  the  sharpening  of  a 

lew  razor,  and  then  that  of  one  which  has  been  rendered  dull 

>y  use. 

Various  kinds  of  whetstones  are  more  or  less  used  in  sharp- 
ening razors,  commonly  in  pieces  measuring  from  eight  to  ten 
inches  long,  by  one  and  a  half  to  two  inches  broad,  and  great 
importance  is  deservedly  attached  to  their  being  perfectly  flat 
on  the  face,  with  which  view  they  are  occasionally  rubbed  on  a 
large  gritstone  with  water,  but  in  use  they  are  always  supplied 
with  oil  and  kept  remarkably  clean. 

The  Charnley  Forest  stone  is  generally  preferred  for  the  first 


1153  SETTING    RAZORS. 

stage  or  for  striking  off  the  wiry  edge  of  the  blade.  The  Turkey 
oilstone  is  sometimes  used  for  the  same  purpose.  The  Green 
hone  or  Welsh  hone,  which  is  harder  than  the  Charnley  Forest, 
and  generally  in  smaller  pieces,  is  occasionally  used  for  razors, 
and  is  by  some  preferred  to  Charnley  Forest  for  finishing  pen 
and  pocket  knives,  and  especially  for  setting  surgeons'  instru- 
ments. 

The  yellow  German  hone,  particularly  the  slabs  from  the 
lower  strata  known  as  old  rock,  is  greatly  preferred  to  all  the 
above  for  the  principal  office  in  setting  razors,  as  it  cuts  more 
slowly,  smoothly,  and  softly,  than  any  of  them.  The  Iron  stone 
or  slabs  of  the  hematite  iron  ore,  are  occasionally  used  for 
giving  the  final  edge,  it  consists  principally  of  oxide  of  iron,  and 
chemically  resembles  crocus,  but  that  it  is  in  a  compact,  instead 
of  a  disentegrated  form.  The  iron  stone  is  however  so  very 
hard  that  it  appears  to  act  more  as  a  burnisher  than  a  hone,  and 
renders  the  edge  almost  too  smooth,  so  that  when  at  all  used, 
the  razor  is  in  general  only  passed  once  or  at  most  twice  on  each 
side  along  the  iron  stone. 

Taking  the  razor  from  the  last  stage  of  its  manufacture 
described  at  page  1051,  it  is  to  be  observed  that  as  the  glazers 
and  polishers  revolve  away  from,  and  not  towards  the  edge,  they 
always  leave  a  thin  filmy  edge,  which  as  the  first  step  towards 
setting,  is  struck  off  on  a  Charnley  Forest  stone.  The  blade  is 
grasped  in  the  right  hand  by  its  tang,  and  near  to  the  cutting 
part,  and  is  placed  square  across  the  one  end  of  the  stone  but 
tilted  about  ten  or  twenty  degrees,  and  is  then  swept  forward 
along  the  stone,  edge  foremost  in  a  circular  arc,  so  as  to  act  on 
the  entire  edge ;  each  side  in  general  receives  only  one  stroke, 
and  this  produces  a  comparatively  obtuse  edge  measuring  from 
forty  to  sixty  degrees.  Should  this  fail  to  remove  the  wiry  edge, 
the  blade  is  placed  perpendicularly  upon,  and  drawn  with  a  little 
pressure  across,  a  strip  of  horn,  (generally  a  spoiled  razor  handle,) 
which  is  fixed  down  to  the  bench,  the  friction  of  the  horn  against 
the  edge  generally  suffices  entirely  to  remove  the  wiry  film, 
otherwise  the  blade  is  struck  once  more  on  each  side  along  the 
stone.  Should  the  film  of  steel  be  left  on  the  stone,  it  is  removed 
before  another  blade  is  applied. 

One  object  in  the  striking  off,  is  to  avoid  the  necessity  for  so  far 
wearing  down  the  back  of  the  razor,  as  to  give  it  the  appearance 


SETTING    RAZORS.  1154 

of  an  old  one  that  has  been  repeatedly  set,  and  it  is  also 
especially  required  in  wide  blades  ground  on  large  stones,  as  the 
wiry  film  is  then  very  difficult  to  remove  otherwise. 

The  next  and  principal  part  of  the  setting  is  accomplished 
almost  invariably  on  the  German  hone.  The  razor  is  held 
as  before,  but  it  is  now  placed  quite  flat  down,  or  so  as  to  touch 
on  the  back  and  edge.  Some  prefer  a  long  sweeping  stroke 
backwards  and  forwards,  others  prefer  small  circular  or  elliptical 
strokes,  and  others  a  short  zig  zag  movement,  but  all  gradually 
work  from  heel  to  point,  or  draw  the  razor  forward  so  as  to  act 
on  all  parts  alike,  and  most  persons  lift  the  razor  endways  towards 
the  conclusion,  allowing  its  point  still  to  rest  on  the  hone,  with 
the  view  of  sharpening  the  circular  end  of  the  blade.  The  choice 
of  these  methods  seems  to  be  principally  a  question  of  individual 
habit,  and  to  be  nearly  immaterial,  provided  the  entire  edge  is 
acted  on  alike,  and  that  at  very  short  intervals  the  razor  is 
turned  over  so  as  to  whet  it  upon  its  opposite  sides  alternately, 
but  it  is  general  to  conclude  the  process  by  sweeping  the  razor 
edge  foremost,  once  on  each  side  steadily  along  the  hone,  as  if  in 
shaving  off  a  thin  slice  of  the  hone,  this  lessens  the  disposition  to 
the  wire  edge. 

The  line  of  policy  is  just  to  continue  this  secondary  process, 
until  the  new  facets  constituting  the  wedge  of  seventeen  to 
twenty  degrees,  exactly  meet  at  the  extremity  of  the  more  obtuse 
angle  given  by  the  striking  off,  and  which  if  mathematically  done, 
would  prevent  the  formation  of  the  wiry  film,  which  is  one  of  the 
most  troublesome  obstacles  in  the  process. 

Should  the  film  nevertheless  arise,  it  is  to  be  removed  by 
passing  the  blade  occasionally  across  the  slip  of  horn,  and  con- 
tinuing the  whetting  for  shorter  periods  on  each  side,  some 
persons  indeed  suffer  the  film  if  very  minute  to  be  abraded  on 
;  the  razor  strop,  but  which  latter  unless  very  cautiously  used  is  a 
very  mischievous  instrument.  It  is  of  course  to  be  understood 
that  the  hone  is  not  given  up,  until  at  any  rate  the  notches  are 
no  longer  perceptible,  when  the  blade  is  drawn  across  the  thumb 
i  or  finger  nail,  which  detects  them  more  faithfully  than  the  slip 
of  horn,  and  that  when  viewed  edgeways,  the  edge  is  merely  dis- 
covered as  the  meeting  of  the  two  sides  of  the  blade,  and  not 
\  from  possessing  itself  any  visible  thickness  or  width. 

As  before  observed,  the  blade  is  by  some  persons  passed  once 

VOL.  in.  K 


1155  RAZOR    STROPS. 


on  each  side  along  the  iron  stone,  but  this  practice  is  by  no 
means  common,  and  may,  according  to  the  questionable  doctrine 
advanced  by  some  cutlers,  spoil  the  blade  by  rendering  it  too 
smooth,  or  too  free  from  the  saw-like  teeth,  but  which  it  would 
appear  can  hardly  be  the  case,  unless  it  also  increase  the  angle 
of  the  edge,  or  render  it  less  acute  and  keen. 

When  the  edge  of  the  razor  admits  of  being  drawn  smoothly 
across  the  horn,  and  the  edge  is  not  distinguishable  by  the  eye, 
the  hone  may  be  considered  to  have  fulfilled  its  purpose,  and  the 
razor  is  slightly  stropped,  but  in  this  case,  as  the  edge  of  the 
blade  becomes  somewhat  embedded  in  the  leather,  it  would  cut 
if  moved  forwards  as  in  setting,  and  therefore  the  razor  is  always 
stropped  backwards,  and  usually  from  heel  to  point. 

Disregarding  the  high  sounding  names  and  praises  bestowed 
on  various  razor  strops,  it  may  be  added  that  within  moderate 
limits,  they  are  the  better  the  harder  their  surfaces,  and  the  less 
they  are  supplied  with  abrasive  matter.  As  when  they  possess 
the  opposite  qualities  of  softness  and  superabundance  of  dressing, 
or  that  they  are  used  in  excess,  they  rapidly  round  the  edge  of 
the  razor,  and  change  its  edge  from  the  well-defined  angle  of 
seventeen  or  twenty  degrees  produced  by  the  stone,  to  twice 
that  angle  or  more,  and  entirely  unfit  it  for  use. 

Perhaps  for  the  razor  strop  a  fine  smooth  surface  of  calf  skin, 
with  the  grained  or  hair  side  outwards,  is  best,  it  should  be 
pasted  or  glued  down  flat  on  a  slip  of  wood,  and  for  the  dressing 
almost  any  extremely  fine  powder  may  be  used,  such  as  impal- 
pably  fine  emery,  crocus,  natural  and  artificial  specular  iron  ore, 
black  lead,  or  the  charcoal  of  wheat  straw ;  each  of  these  two 
latter  act  as  abrasives  in  consequence  of  containing  a  minute 
portion  of  silex.  Combinations  of  these  and  other  fine  powders, 
mixed  with  a  little  grease  and  wax,  have  been  with  more  or  less : 
of  mystery  applied  to  the  razor  strop.  The  choice  appears  nearly 
immaterial,  provided  the  powders  are  exceedingly  fine,  and  they 
are  but  sparingly  used. 

One  side  of  the  strop  is  generally  charged  with  composition ; 
on  the  other  side  the  leather  is  left  in  its  natural  state,  and  the 
finishing  stroke  is  in  general  given  on  the  plain  side. 

It  is  of  great  importance  that  all  razor  strops  be  kept  scrupu- 
lously clean,  and  with  which  view  they  are  provided  with  sheaths, 
which  should  be  marked  so  as  to  prevent  the  composition  being 


SHARPENING   CUTTING    TOOLS    WITH    ARTIFICIAL    GRINDERS.     1156 

accidentally  carried  over  to  the  clean  side  of  the  instrument.  The 
strop  should  be  always  employed  in  the  most  sparing  manner,  so 
as  rather  to  wipe  than  rub  the  razor ;  many,  indeed,  never  strop 
the  razor  after  use,  but  simply  wipe  it  dry  on  clean  wash  leather, 
a  silk  handkerchief,  or  a  soft  towel,  and  only  employ  the  strop 
before  using  the  razor.  A  good  mode  was  suggested  to  preserve 
the  edges  of  surgical  instruments  from  rusting  when  laid  by, 
namely,  the  drawing  them  lightly  through  a  tallow  candle ;  this 
leaves  a  minute  quantity  of  grease  on  the  edge,  which  defends 
(them  from  the  air,  and  becomes  deposited  on  the  strop  before 
Ithe  blade  is  used. 

When  a  razor,  from  continued  use  and  stropping,  has  become 
jdull,  it  mostly  arises  from  the  edge  having  been  rounded  and 
thickened  as  explained  by  the  diagram,  figs.  1037  and  1038  ;  in 
this  case  the  setting,  if  attempted  by  the  amateur,  may  with 
advantage  be  only  so  far  pursued  as  barely  to  remove  the  rounded 
part.  On  close  inspection  it  will  be  seen  the  part  of  the  facet 
towards  the  back  is  first  touched  by  the  hone,  the  effect  of  which 
is  seen  by  the  less  polished  surface  it  leaves ;  and  if  the  setting  be 
only  continued  until  the  bright  rounded  part  is  all  but  removed 
when  examined  with  a  magnifier,  no  wire  will  be  formed,  and  the 
blade  will  be  again  brought  within  the  province  of  the  razor 
strop.  The  razor,  after  having  been  repeatedly  set,  becomes  so 
wide  in  the  bevil  or  facet,  as  to  require  to  be  re-ground,  to  thin 
t  away  to  the  first  state,  as  the  blade  should  always  be  so  thin 
as  to  be  sensibly  pliant  at  the  extreme  edge,  when  pressed  flat 
on  the  thumb  nail  and  slightly  tilted  ;  but  the  re-grinding  should 

done  with  a  proper  regard  to  the  relative  width  of  the  back  of 
the  blade,  and  the  preservation  of  its  proper  temper. 


SECT.    IV. SHARPENING    CUTTING    TOOLS  WITH    ARTIFICIAL    GRINDERS. 

FIG.  1039  represents  the  upper  part  of  a  horizontal  grinding 
machine,  principally  intended  for  grinding  and  setting  the  edges 
jof  cutting  tools,  by  means  of  revolving  laps  of  metal  fed  with  the 
various  abrasive  powders.  The  lower  part  of  this  apparatus 
exactly  resembles  that  of  the  vertical  grinding  machine,  fig.  1030, 
page  1132,  but  to  place  the  sides  of  the  laps  in  a  horizontal  posi- 
tion, this  apparatus  is  furnished  with  a  vertical  spindle,  or 

K2 


1157 


HORIZONTAL    GRINDING    MACHINE. 


mandrel,  upon  which  the  laps  are  screwed  after  the  manner  of 
chucks  upon  an  ordinary  turning  lathe. 

The  mandrel  is  mounted  in  a  rectangular  frame  of  cast  iron, 
which  fits  between  the  bearers,  and  is  secured  in  its  place  by  a 
wedge  beneath,  as  shown  at  w.  The  upper  side  of  the  iron 
frame  is  made  as  a  platform,  and  is  fitted  in  the  center  with  a 
cylindrical  steel  collar,  within  which  the  mandrel  revolves,  while 
its  lower  end  rests  upon  a  center  screw  passing  through  the 
bottom  of  the  iron  frame,  and  by  means  of  which  the  mandrel  can 
be  elevated  to  the  required  position,  nearly  level  with  the  upper 
metal  platform,  which  is  dotted  in  the  drawing,  and  serves  as  a 
support  for  the  tools.  This  second  platform  stands  upon  three  feet, 
which  are  fitted  with  pins  that  enter  corresponding  holes  in  the 
under  platform ;  by  this  arrangement  the  upper  platform  can  be 
readily  removed  when  the  laps  are  exchanged.  The  band  for 
driving  the  mandrel  proceeds  from  the  foot  wheel  over  the  two 
oblique  guide  pulleys  g,  to  the  pulley  T/Z,  fixed  on  the  vertical 


FIGS.  1039. 


1040. 


mandrel,  and  the  tension  of  the  band  is  adjusted  by  shifting  the 
mandrel  frame  to  the  right  or  left  upon  the  bearers. 

The  general  application  of  the  revolving  laps  has  been  alread} 
described  in  the  Catalogue  of  Abrasive  Processes,  under  the 
head  WHEELS,  articles  37  to  47,  pages  1113  to  1117,  and  it  onh 
remains  to  observe,  that  the  lead  lap  supplied  with  emery  o 
different  degrees  of  coarseness,  is  used  for  grinding  the  tools  t< 


GUIDES    FOR    GRINDING    TOOLS    TO    DEFINITE    ANGLES.  1158 

the  required  angle  ;  they  are  afterwards  smoothed  upon  the 
brass  lap  fed  with  flour  emery,  or  oilstone  powder,  and  the  final 
polish  is  given  with  the  iron  lap  supplied  with  crocus ;  the  two 
latter  powders  may  be  applied  either  by  putting  on  the  oil  and 
powder  separately  in  small  quantities,  and  mixing  them  with  a 
brush,  or  the  materials  may  be  mixed  in  a  cup  previous  to  their 
application. 

Various  guides  have  been  employed  for  determining  the  exact 
angle  at  which  the  tools  should  be  applied  to  the  revolving  laps, 
and  also  to  remove  the  difficulty  of  grinding  the  bevils  of  the 
tools  perfectly  flat,  the  most  simple  guide  consists  of  a  block  of 
wood  shown  in  fig.  1040,  and  made  to  the  same  angle  at  which 
it  is  required  to  grind  the  tool,  the  block  is  screwed  upon  the 
upper  platform  of  the  horizontal  grinding  machine,  and  the  back 
of  the  tool  being  held  steady  upon  the  bevilled  side  of  the 
wooden  guide  block,  the  chamfer  of  the  tool  is  readily  ground  to 
that  particular  angle,  this  method  however  requires  a  separate 
guide  for  every  different  angle. 

An  instrument  that  has  been  called  a  quadrant  rest  is  shown 
in  fig.  1041,  and  which  removes  the  necessity  for  several  guide 
blocks,  this  instrument  is  made  of  brass,  and  consists  of  a  base 
piece  that  is  let  into  the  platform  of  the  horizontal  grinding 
machine,  a  rising  plate  R  is  connected  to  the  base  piece  by  a 
joint  at  the  edge  close  to  the  lap,  and  it  is  retained  at  any 
required  angle  by  the  arch  piece  and  binding  screw  S,  a  steel  rib 
is  fitted  on  the  upper  surface  of  the  rising  plate  against  which 
the  tool  is  held  whilst  being  ground. 

For  determining  the  exact  angle  at  which  the  instrument  is 
fixed,  the  arch  piece  is  either  graduated  into  degrees,  or  small 
holes  are  drilled  at  every  five  degrees,  into  which  the  point  of  the 
|  binding  screw  enters.  The  tool  to  be  ground  is  held  with  its 
back  upon  the  upper  surface,  and  one  side  in  contact  with  the 
steel  rib,  but  the  quadrant  rest  like  the  wooden  guide  blocks,  is 
unprovided  with  the  means  of  determining  the  horizontal  angle  of 
the  tool,  which  is  therefore  left  to  the  dexterity  of  the  operator ; 
they  are  both  objectionable  also  on  account  of  always  presenting 
the  tool  to  the  same  part  of  the  lap,  which  is  thereby  liable  to  be 
worn  irregularly.  These  objections  are  entirely  removed  in  the 
instrument  next  described. 

The  instrument  for  grinding  and  setting  ordinary  turning  tools 


1159 


INSTRUMENT    FOR    GRINDING    AND    SETTING 


having  rectilinear  edges  shown  in  figs.  1042  to  1045,  is  a  modi- 
fication of  an  instrument  that  has  been  long  used  for  sharpening 
the  ends  of  tools  employed  in  eccentric  and  ornamental  turning, 
for  which  works  the  tools  are  in  general  all  of  one  exact  size,  and 
therefore  admit  of  being  held  in  the  same  socket,  but  this  would 
not  answer  for  the  common  turning  tools  made  of  different  sizes 
according  to  their  respective  purposes. 

The  principle  employed  in  the  construction  of  the  instrument 
fig.  1042,  is  to  fix  the  tool  to  be  ground  to  a  triangular  frame 
having  two  points  of  bearing,  and  allow  the  point  of  the  tool  to 
be  ground  to  form  the  third  bearing,  if  therefore  the  two  feet  of 
the  instrument  are  supported  on  a  plane  parallel  with  the 


FIG.  1042. 


grinding  lap,  whilst  the  third  leg  of  the  triangle,  or  the  tool 
to  be  ground,  rests  upon  the  revolving  lap,  the  latter  will  grind 
away  the  tool  until  its  surface  agrees  throughout  with  the 


ORDINARY    TURNING    TOOLS.  1160 

plane  of  the  lap,  and  in  consequence  the  end  of  the  tool  will 
ultimately  be  made  perfectly  flat. 

As  however  tools  for  turning  are  required  to  possess  a  variety 
of  forms,  some  square,  others  bevilled  or  pointed,  others  to  cut 
at  the  side,  and  that  their  edges  should  be  more  or  less  acute, 
according  to  the  material  upon  which  they  are  employed,  it  is 
essential  to  give  the  socket  which  holds  the  tool  two  adjustments, 
the  one  vertical,  the  other  horizontal,  and  both  furnished  with 
divisions  and  clamping  screws  for  determining  every  required 
position  to  be  given  to  the  tools. 

The  general  arrangement  of  the  instrument  will  be  sufficiently 
obvious  from  an  inspection  of  fig.  1042,  in  which  A,  represents 
the  base  of  the  instrument  on  which  is  fixed  the  vertical  arch-piece 
B,  an  adjustable  plane  C,  is  connected  with  the  base  by  a  joint 
at  D,  on  which  it  moves,  and  may  be  fixed  by  the  binding  screw 
E,  at  any  angle  from  0,  at  the  top  of  the  arc  B  to  60  degrees, 
lower  than  which  it  is  never  required  to  be  placed,  the  upper 
part  of  the  plane  C,  has  a  circular  mortise,  and  is  graduated 
through  an  arc  of  50  degrees  on  each  side  of  the  central  line. 
The  piece  G,  which  serves  as  the  bed  for  the  tool  to  be  ground, 
is  bevilled  on  its  front  edge  that  it  may  not  come  in  contact  with 
the  lap,  and  a  pointed  rectangular  bar  proceeds  from  the  back 
of  this  piece  to  the  circle  of  graduations  on  the  plane  C,  to  which 
the  bed  piece  G,  is  united  by  means  of  a  pivot  a  little  in  advance 
of  D,  consequently  the  bed  piece  is  capable  of  being  moved  to 
the  right  or  left,  and  it  can  be  fixed  at  any  angle  on  the 
graduated  arc,  by  means  of  a  capstan  headed  screw  passing  from 
beneath  the  plate  C,  through  the  circular  mortise  into  the  upper 
end  of  the  bar  on  G. 

On  the  upper  surface  of  the  piece  G  is  a  steel  plate  H,  fastened 
by  two  square  headed  screws,  z,  i,  this  plate  has  a  spring  under- 
neath which  raises  the  plate  to  admit  the  tool  which  is  to  be 
ground.      The  four  screws  marked  k  are  for   regulating   the 
height  of  the  steel  plate,  so  as  to  leave  the  same  opening  between 
i  the  plates  on  the  side  unoccupied,  as  on  that  where  the  tool  is 
i  fixed,  the  application  of  these  screws  is  shown  in  figs.  1043  to 
1045,  which  represent  the  manner  in  which  different  tools  are 
fixed  in  the  instrument. 

A  flat  tool  is  held  as  in  fig.  1043  the  small  screws  3  and  4  are 
r  each  withdrawn  a  little  below  the  surface  of  the  steel  plate,  and 


1161    INSTRUMENT    FOR    GRINDING    ORDINARY    TURNING    TOOLS. 


the  screws  1  and  2  are  projected  forwards  for  the  support  of  th< 
same,  the  screw  1  being  as  much  in  advance  of  the  plate  as  th< 
thickness  of  the  tool  at  3,  and  the  projection  of  the  screw 
being  equal  to  the  thickness  of  the  tool  at  4,  now  therefore  th< 
steel  plate  will  be  supported  equally  on  every  side,  and  it  will  beai 
flat  on  the  tool,  and  hold  it  firmly  when  the  steel  plate  is  clamp( 
by  the  square  headed  screws.  Without  the  aid  of  the  screws  foi 


1044. 
X 


1045. 


2  /« 


U 


supporting  the  plate  on  the  opposite  side  to  the  tool,  it  would 
only  bear  upon  the  edge  of  the  tool  and  would  not  hold  it  firmly, 
the  adjustment  of  the  small  screws  however  admits  of  the  tool 
being  firmly  fixed,  notwithstanding  that  it  may  be  of  irregular 
thickness. 

Point  tools  to  be  ground  at  angles  not  exceeding  50  degrees, 
may  be  clamped  in  the  same  manner  as  flat  tools,  and  the  angular 
position  be  obtained  by  shifting  the  point  of  G  to  the  required 
graduation  on  the  plane  C,  the  socket  is  then  secured  by  the 
capstan  screw.  When  the  angle  of  the  tool  exceeds  50  degrees 
it  is  clamped  in  the  manner  next  described. 

Bevil  tools  are  more  conveniently  fixed  as  in  fig.  1044,  in 
which  case  the  screw  4  is  withdrawn,  and  1,  2,  and  3,  are 
advanced  to  equal  the  thickness  of  the  tool. 

Side  cutting  tools  are  held  as  in  fig.  1045,  screws  2  and  4 
being  withdrawn,  and  1  and  3  adjusted  to  the  thickness  of  the 
tool. 

The  tool  having  been  firmly  clamped,  the  vertical  and  hori- 
zontal angles  are  adjusted  until  the  chamfer  of  the  tool  bears 


INSTRUMENT    FOR    SETTING    ROSE    ENGINE    TOOLS. 


1162 


fairly  upon  the  lap,  when  the  two  legs  of  the  instrument  rest 
upon  the  platform  of  the  grinding  machine.  To  avoid  the  rapid 
deterioration  of  the  lap,  it  is  desirable  to  distribute  the  wear  by 
applying  the  tools  to  different  parts  of  the  lap  in  succession.  For 
grinding  the  tools  to  definite  angles,  this  instrument  is  adjusted 
in  the  same  manner  as  the  corresponding  instrument  for  setting 
angular  tools  for  ornamental  turning,  described  on  pages  1164  to 
1169. 


Fig.  1046,  represents  an  instrument  that  is  very  generally 
iployed  by  practical  rose  engine  turners,  for  sharpening  their 
lall  angular  sliding  rest  tools,  which  require  a  considerable  degree 
accuracy.     This  instrument   is   provided   with    two    planes 
ointed  together,  upon  the  one  of  which  the  tool  to  be  sharpened, 


is  placed  in  the  required  position  for  grinding  the  horizontal 
angle  of  the  edge,  whilst  the  second  plane  serves  for  determining 


1163  INSTRUMENT    FOR    SETTING    ROSE    ENGINE    TOOLS. 

the  vertical  angle  of  the  chamfer.  The  instrument  is  generally 
attached  to  the  frame  of  the  lathe,  but  to  render  it  portable  it  is 
sometimes  fixed  to  a  block  of  wood  sufficiently  heavy  to  give  it 
stability ;  the  tool  to  be  ground  is  held  nearly  stationary  by  the 
left  hand,  while  a  piece  of  oilstone,  or  other  abrasive  is  rubbed 
with  the  right  hand  on  the  chamfer  of  the  tool. 

The  instrument  consists  of  a  horizontal  brass  plate  A  fig. 
1046,  having  a  circular  mortise,  and  a  graduated  arc  for  denoting 
the  angle  at  which  the  central  guide  bar  B  is  placed,  this  bar 
moves  upon  a  pivot  near  the  front  edge  of  the  plate  A,  and  is 
fixed  in  any  angular  position  by  the  clamping  screw,  passing 
through  the  circular  mortise.  The  vertical  plate  C,  is  jointed 
near  its  middle  to  the  edge  of  the  plate  A ,  and  can  be  fixed  at 
any  inclination  within  its  range,  by  means  of  the  arc  and  clamp- 
ing screw  D.  This  plate  has  a  central  rectangular  opening 
through  which  the  end  of  the  tool  may  project  as  seen  in  the 
figure,  in  order  to  allow  of  the  action  of  the  grinder,  which  is 
sometimes  a  flat  piece  of  oilstone  about  three  inches  square 
embedded  in  a  wooden  stock,  at  other  times  a  piece  of  hard  brass 
supplied  with  fine  flour  emery  or  oilstone  powder,  is  used  as  the 
grinder,  this  retains  a  level  surface  for  a  longer  period  than  the 
oilstone,  which  must  be  occasionally  ground  flat  upon  a  level 
plate  charged  with  emery. 

In  using  this  instrument,  the  tool  to  be  sharpened  is  laid  face 
downwards  upon  the  horizontal  plate,  and  with  the  side  of  the 
tool  in  contact  with  the  guide  bar,  which  is  fixed  at  the  angle 
required  for  the  horizontal  edge  of  the  tool,  the  second  plate  is 
then  adjusted  to  give  the  required  bevil  to  the  chamfer  of  the 
tool.  The  oilstone  moistened  with  a  few  drops  of  oil  is  applied 
with  its  face  flat  upon  the  vertical  plate,  and  the  tool  is  advanced 
with  the  fingers  of  the  left  hand,  until  its  end  touches  the  oil- 
stone, which  is  rubbed  in  contact  with  the  vertical  plate  in  all 
directions  by  the  right  hand,  while  the  end  of  the  tool  is  kept 
gently  pressing  against  the  oilstone,  this  is  continued  until  the 
chamfer  of  the  tool  is  sufficiently  sharpened.  If  it  be  an  angular 
tool  the  position  of  the  guide  bar  is  then  changed,  and  the 
second  chamfer  is  operated  upon  in  the  same  manner ;  and 
lastly  the  face  of  the  tool  is  laid  flat  on  the  oilstone,  and  gently 
rubbed  to  remove  any  trifling  burr  that  may  have  formed  upon 
the  edge.  It  is  of  course  necessary  that  the  tool  should  be  held 


TOOLS    FOR    ECCENTRIC    AND    ORNAMENTAL    TURNING.          1164 

quite  steadily  in  its  position  on  the  bed  of  the  instrument,  not- 
withstanding that  it  is  kept  constantly  pressed  endways  against 
the  oilstone. 

Angular  tools  that  are  used  for  rose  engine  turning  on  curved 
surfaces  such  as  those  of  watch  cases,  are  generally  ground  with 
the  one  angle  of  the  edge  of  nearly  twice  the  length  of  the  other, 
this  is  done  to  give  the  tool  increased  strength,  and  allow  of  a 
rubber  with  a  rounded  end  being  fixed  near  to  the  point  of  the 
tool,  to  regulate  its  penetration. 


The  various  small  tools  with  straight  and  angular  edges, 
employed  for  eccentric  and  ornamental  turning,  are  required  to 
have  very  accurate,  keen,  and  highly  polished  edges,  in  order 
that  they  may  impart  the  same  degree  of  excellence  and  finish 
to  the  work,  whether  executed  with  tools  fixed  in  the  slide  rest, 
or  with  revolving  cutters  employed  in  the  various  apparatus  that 
will  be  described  in  a  future  volume.  These  ornamental  works, 
from  their  intricate  and  delicate  character,  scarcely  admit  of  any 
polishing,  and  therefore  the  beauty  and  finish  of  their  surfaces 
depend  almost  exclusively  upon  the  perfection  of  the  cutting 
edges  of  the  tool,  as  the  good  or  bad  quality  it  may  possess,  is 
literally  copied  upon  the  work,  without  the  possibility  of  subse- 
quent correction.  It  is  therefore  highly  desirable  that  the  edges 
of  the  tools  should  be  formed  by  perfectly  true  planes,  polished 
in  the  most  careful  manner,  results  which  cannot  be  obtained 
without  the  assistance  of  suitable  guides  for  holding  the  tool,  and 
the  employment  of  the  most  delicate  abrasive  powders. 

The  instrument  for  setting  straight  and  angular  tools  for  orna- 
mental turning  shown  in  fig.  1047,  resembles  in  principle  and  con- 
struction the  instrument  for  grinding  common  turning  tools  on  the 
revolving  lap,  described  on  page  1159,  but  fig.  1047,  has  greater 
range  in  the  angles  to  which  the  tools  may  be  set,  and  it  is  also 
provided  with  a  more  suitable  socket  for  the  reception  of  these 
small  tools,  which  are  made  of  one  uniform  size  in  their  shanks 
or  stems,  in  order  that  they  may  all  fit  the  same  socket  of  the 
sliding  rest  in  which  they  are  to  be  used.  Fig.  1047  is  employed 
in  the  reverse  manner  to  the  instrument  for  grinding  common 
turning  tools,  as  instead  of  the  tool  being  held  stationary  upon 
a  revolving  lap,  the  tool  when  fixed  in  the  instrument  for  angular 


1165 


INSTRUMENT    FOR    SHARPENING    STRAIGHT 


tools,  is  rubbed  first  upon  a  stationary  piece  of  oilstone,  and  sub- 
sequently set  and  polished  in  like  manner  upon  flat  plates  of 
metal  supplied  with  oilstone  powder  or  crocus. 

The  case  for  containing  the  instrument  for  setting  angular 
tools,  has  three  slabs  of  mahogany,  measuring  about  eight  inches 
long,  and  six  and  a  half  inches  wide,  fitted  as  drawers ;  into  the 


FIG.  1047 


B 


one  side  of  each  of  the  drawers,  and  close  to  the  edge,  are  inlaid 
respectively,  a  piece  of  oilstone,  brass,  and  cast  iron,  about  three 
and  a  half  inches,  by  three  inches.  The  upper  surfaces  of  these 
plates  are  made  quite  flat,  and  they  project  slightly  above  the  wood 
as  shown  in  fig.  1 047,  in  which  the  one  edge  of  the  angular  tool  is 
supposed  to  rest  upon  the  metal  plate,  whilst  the  two  feet  of  the 
instrument  stand  upon  the  mahogany  slab,  which  is  sufficiently 
large  to  support  them  whilst  the  tool  is  traversed  in  all  directions 
over  the  metal  plate. 


AND    ANGULAR    TOOLS    FOR    ORNAMENTAL    TURNING.  1166 

In  fig.  1047,  the  same  letters  of  reference  are  used  for  corres- 
ponding parts  as  for  fig.  1042,  and  the  description  of  the  latter 
instrument  on  page  1 160,  is  equally  applicable  to  fig.  1047?  except 
that  the  graduated  arc  on  C,  is  extended  to  75  degrees  on  each 
side  of  the  central  line,  and  the  socket  G  is  made  as  a  straight 
bar  with  two  projecting  pieces  having  rectangular  openings  to  fit 
the  shafts  of  the  tools,  which  are  fixed  by  the  binding  screw  /. 

To  sharpen  an  angular  tool  of  30  degrees,  the  instrument  is 
adjusted  as  shown  in  fig.  1047.  The  index  point  of  the  socket  G, 
is  placed  at  the  division  marked  30  on  the  arc  C,  which  is  then 
adjusted  on  the  vertical  arc  B,  to  the  angle  required  for  the 
chamfer  of  the  tool ;  in  the  drawing  this  is  supposed  to  be  30 
degrees,  the  tool  is  then  placed  in  the  socket  G,  and  the  distance 
which  it  should  project  from  the  socket,  is  determined  by  placing 
the  instrument  in  the  position  shown  in  the  figure,  with  its  two 
legs  upon  the  wood  surface,  and  the  edge  of  the  tool  resting  upon 
the  oilstone.  The  projection  of  the  tool  is  then  so  regulated  that 
the  base  piece  A,  may  be  parallel  with  the  wood  surface,  when 
the  tool  is  fixed  by  the  binding  screw  /.  Should  the  projection 
the  tool  be  such  that  the  base  of  the  instrument  is  inclined  to 
the  wood  surface,  the  chamfer  of  the  tool  would  not  be  ground 
to  an  angle  of  30  degrees;  the  precise  angle  of  the  chamfer  is 
however  not  generally  very  important. 

The  instrument  having  been  adjusted,  the  next  operation  is  to 
sharpen  the  tool  upon  the  oilstone,  which  is  moistened  with  a  few 
drops  of  oil,  and  the  tool  is  applied  as  shown  in  the  drawing,  and 
lightly  rubbed  with  circular  or  elliptical  strokes  in  all  directions 
>ver  the  surface  of  the  stone,  until  a  keen  edge  is  produced  upon 
angle  of  the  tool.  The  index  point  of  the  socket  G  is  then 
shifted  to  30  degrees  on  the  opposite  side  of  the  circle  of  gradua- 
tions on  the  piece  C,  and  the  second  edge  of  the  tool  is  sharpened 
in  the  same  manner. 

The  tool  having  been  completely  sharpened  upon  the  oilstone, 
is  next  taken  to  the  metallic  surfaces  to  have  its  edges  polished, 
and  which  is  done  in  the  following  manner.  Without  unfixing 
the  tool,  the  plate  C  is  moved  about  2  degrees  higher  upon  the 
arc  B,  and  the  tool  is  then  applied  upon  the  brass  surface,  which 
is  supplied  with  a  very  small  quantity  of  oilstone  powder  and  oil. 
The  tool  is  rubbed  upon  the  brass  surface  in  the  same  manner  as 
upon  the  oilstone,  until  the  chamfer  presents  a  narrow  facet  with 


1167 


SHARPENING    TOOLS    FOR    ORNAMENTAL    TURNING. 


a  dull  greyish  polish;  when  both  edges  of  the  tool  have  been 
thus  treated,  the  tool  is  very  carefully  wiped  to  remove  every 
particle  of  oilstone  powder,  and  the  final  polish  is  given  by 
rubbing  the  tool  upon  the  iron  surface,  which  is  supplied  with  a 
little  crocus  and  oil. 

The  upper  surface  of  the  tool,  or  the  flat  face,  should  be  kept 
in  very  good  condition  towards  the  cutting  edges,  this  is  effected 
by  removing  the  tool  from  the  instrument  and  laying  its  face  flat 
upon  the  iron  surface,  upon  which  the  tool  is  rubbed  with  the 
fingers  until  the  slight  burr  thrown  up  in  the  sharpening  is 
removed. 

Small  tools,  such  as  the  revolving  cutters  used  in  the  various 
cutting  frames  employed  for  ornamenting  the  surfaces  of  turned 
works,  are  from  necessity  made  too  short  to  be  held  in  the 
instrument,  fig.  1047  ;  in  this  case  they  are  first  clamped  in  a 
tool-holder  having  a  rectangular  hole  suited  to  the  size  of  the 
stem  of  the  tool,  which  is  clamped  therein  by  a  square-headed 

FIGS.  1048. 


15 


\ 


\ 


30 


\ 


45 


1051. 


1052. 


1053. 


binding  screw,  as  shown  in  fig.  104<9,  which  represents  a  tool- 
holder  adapted  for  revolving  cutters  of  a  medium  size.  The 
stem  of  the  tool-holder  is  made  to  fit  the  socket  G,  of  the  instru- 


ANGLES    OF    TOOLS    FOR    ORNAMENTAL    TURNING.  1168 

ment,  fig.  1047,  in  which  it  is  secured  exactly  as  described  for 
the  slide  rest  tool,  shown  detached  in  fig.  1048. 

Drills,  such  as  fig.  1053,  intended  to  be  used  in  the  drilling 
instrument  for  ornamental  turning,  are  in  like  manner  fixed  in  a 
holder,  as  shown  in  fig.  1050  ;  but  in  this  case  the  binding  screw 
is  not  required,  as  the  stem  of  the  drill  fits  the  cylindrical  hole 
in  the  holder,  and  it  is  prevented  from  twisting  round  by  a  short 
projecting  piece  at  the  end,  which  is  filed  down  to  the  diametrical 
line,  so  as  to  slide  into  the  flat-bottomed  recess  in  the  holder, 
and  also  to  fit  the  drilling  instrument  in  which  it  is  to  be 
employed,  as  shown  in  fig.  489,  page  555,  Vol.  II. 

To  avoid  uncertainty  respecting  the  angles  of  the  tools  used 
for  ornamental  turning,  they  are  usually  stamped  with  figures 
denoting  the  angles  at  which  the  tools  are  ground  ;  but  it  should 
be  remembered  that  these  numbers  are  measured  from  a  line  at 
right  angles  to  the  center  of  the  tool,  or,  in  other  words,  it  is  the 
angle  which  is  ground  away,  that  is  estimated,  and  not  the  angle, 
which  the  edges  of  the  tool  make  to  each  other.  Thus,  in  the 
instance  of  the  tool  just  described  as  being  ground  at  the  angle 
of  30  degrees,  each  side  of  the  tool  is  ground  at  an  angle  of 
30  degrees,  or  the  edges  differ  to  that  extent  from  a  flat  tool,  and 
the  sum  of  these  two  angles  being  60  degrees,  it  follows  that  the 
edges  of  the  tool  meet  each  other  at  an  angle  of  ]  20  degrees,  or 
the  complement  to  the  sum  of  the  two  angles  at  which  the  tool  is 
ground. 

This  will  be  more  distinctly  seen  in  figs.  1051  to  1053,  which 
represent  the  plan  of  three  tools  of  different  angles.  Fig.  1051 
shows  a  single  bevil  tool  ground  at  an  angle  of  15  degrees  ;  and 
consequently  the  edge  of  this  tool  will  meet  its  side  at  an  angle  of 
75  degrees,  or  the  difference  between  15  degrees  and  90  degrees, 
which  latter  is  of  course  the  angle  formed  by  the  edge  of  a  flat 
tool  with  its  side,  when  it  is  ground  perfectly  square.  Fig.  1052 
represents  the  plan  of  an  angular  tool  ground  on  both  bevils  at 
an  angle  of  30  degrees,  and,  as  just  explained,  its  edges  will 
meet  at  120  degrees,  or  the  difference  between  60  degrees,  the 
sum  of  the  two  angles  ground  away,  and  180  degrees,  or  the 
straight  edge  of  a  flat  tool.  The  drill,  fig.  1053,  is  ground  at  two 
angles  of  45  degrees,  and  the  sum  of  these  being  90  degrees,  it 
follows  that  its  edges  form  an  angle  of  90  degrees. 

The  vertical  angle,  at  which  the  tools  are  sharpened,  is  in  like 


1169 


VERTICAL   LAP    FOR   SETTING   TOOLS. 


manner  estimated  by  the  angle  ground  away;  thus,  when  the 
piece  C,  fig.  1047,  is  elevated  to  0  on  the  arc  B,  the  tool  is 
ground  quite  square,  or  at  an  angle  of  90  degrees,  and  when 
placed  at  division  10  the  chamfer  of  the  tool  differs  10  degrees 
from  the  right  angle,  or  it  forms  an  angle  of  80  degrees  with  the 
face  of  the  tool,  and  so  on  of  other  numbers. 

The  instrument  for  setting  angular  tools,  fig.  1047,  is  some- 
times used  with  the  horizontal  grinding  machine,  fig.  1039  ;  it  is 
then  applied  in  exactly  the  same  manner  as  the  instrument  for 
grinding  ordinary  turning  tools.  At  other  times  the  lap  is 
screwed  upon  the  mandrel  of  a  lathe,  so  as  to  revolve  vertically, 


FIG.  1054. 


in  exactly  the  same  manner  as  a  surface  chuck ;  but  in  this  case 
it  is  necessary  to  provide  a  support  for  the  two  legs  of  the  instru- 
ment, and  which  generally  consists  of  a  block  of  wood  mounted 
on  a  base  piece  similar  to  that  of  a  common  turning  rest.  This 
arrangement  is  shown  in  fig.  1054,  in  which  A  represents  the 


SHARPENING   TOOLS  WITH    CONCAVE    EDGES.  1170 

lap,  B  the  wooden  block,  which  measures  about  4^  inches  wide 
and  1^  inches  thick,  held  by  two  screws  to  the  iron  base  C, 
which  is  secured  to  the  bearers  by  the  rest  bolt,  not  seen  in  the 
drawing,  but  which  allows  of  the  wooden  block  being  adjusted, 
so  that  its  side  may  be  in  a  line  with  the  face  of  the  lap,  when 
tested  by  a  straight  edge  applied  to  both.  The  wooden  block 
then  serves  the  same  purpose  as  the  platform  of  the  horizontal 
grinding  machine,  and  the  instrument  is  applied  in  a  similar 
manner,  except  that  it  is  held  vertically,  as  shown  in  the  figure, 
which  represents  the  application  of  the  instrument  to  setting 
detached  angular  blades  for  cutting  the  threads  of  screws,  and 
adapted  to  tool-holders,  such  as  fig.  608,  page  630,  Vol.  II.  For 
sharpening  these  blades  a  different  form  of  socket  is  adopted,  in 
order  that  tools  of  various  depths  and  thicknesses  may  be  securely 
clamped.  This  socket  consists  of  a  flat  bar  of  steel  with  two 
projecting  sides  at  the  front  extremity,  as  seen  in  the  drawing ; 
the  tool  to  be  sharpened  is  placed  in  the  channel,  and  held  in  its 
position  by  the  small  side  screw,  s.  The  instrument  is  then 
adjusted  to  the  angle  required  for  the  depth  of  the  thread  of  the 
screw,  and  which  has  been  already  explained  in  Section  IX.  of 
the  Chapter  on  Screws,  Vol.  II. 


Concave  tools,  whose  edges  when  seen  in  plan  form  part  of  a 
circular  line,  such  as  the  bead,  astragal,  and  quarter  hollow  tools, 
figs.  395  to  398,  page  519,  Vol.  II.,  are  most  conveniently  and 
accurately  ground  upon  conical  grinders  fed  with  flour  emery,  or 
other  abrasive  powders,  after  the  manner  of  laps  ;  these  grinders 
are  in  the  form  of  long  cones  of  small  diameter,  so  that  some 
part  of  their  circumference  may  agree  with  the  curve  of  the  tool, 
which  may  be  then  ground  with  great  accuracy  to  the  circular 
form. 

Bead  tools,  exceeding  about  half  an  inch  wide,  are  commonly 
ground  upon  a  soft  iron  cone,  fig.  1055,  about  seven  inches  long, 
one  inch  and  a  half  diameter  at  the  larger  end,  and  half  an  inch 
at  the  smaller.  The  cone  is  mostly  furnished  with  a  square  tang 
at  a  to  fit  the  square  hole  chuck  of  the  turning  lathe  in  which  it 
is  mounted,  the  smaller  end  of  the  cone  being  pierced  in  the 
center  with  a  conical  hole  for  the  reception  of  the  center  point 
of  the  popit  head.  For  tools  less  than  about  half  an  inch  wide, 

VOL.  III.  L 


1171 


CONICAL    GRINDERS    FOR    BEAD    TOOLS    AND    DRILLS. 


shorter  cones  are  used,  and  which  are  fixed  in  a  plain  chuck,  as 
shown  at  fig.  1056,  so  as  to  be  supported  at  the  one  end  only,  as 


FIGS.  1055. 


1056. 


the  lesser  end  of  the  cone  is  too  small  to  admit  of  the  support  of 
the  popit  head,  and  which  is  also  less  required  with  the  shorter 
cone. 

The  cone  having  been  turned  true,  and  its  surface  slightly 
roughened  by  drawfiling,  it  is  then  charged  with  flour  emery  and 
oil,  and  the  tool  is  applied  to  that  part  of  the  cone  which  fits  the 
curve  :  and  with  the  face  of  the  tool  towards  the  small  end  of  the 
cone,  in  order  that  the  lower  side  of  the  tool  may  be  ground  to 
a  larger  diameter,  to  give  the  proper  angle  of  penetration  to  the 
chamfer  of  the  tool  at  all  parts  of  the  curve.  Large  tools,  which 
only  require  a  moderate  degree  of  accuracy,  are  finished  upon  a 
corresponding  cone  of  lead,  or  hard  wood,  fed  in  like  manner 
with  flour  emery  and  oil,  the  emery  becomes  embedded  in  the 
wood,  and  consequently  gives  a  higher  polish  to  the  chamfer  of 
the  tool,  the  rectilinear  corners  of  which  are  sharpened  upon 
a  flat  oilstone,  and,  lastly,  the  face  of  the  tool  is  rubbed  on 
the  oilstone  to  remove  the  wire  edge.  Quarter  hollow  tools 
are  treated  in  exactly  the  same  manner  as  bead  tools  and 
astragals. 

Bead  tools,  bead  drills,  and  revolving  cutters,  less  than  about 
one  quarter  of  an  inch  wide,  that  are  used  in  the  various  appa- 
ratus for  ornamental  turning,  although  ground  in  the  same 
manner,  require  to  have  more  accurate  and  highly-polished 
surfaces,  as  was  explained  in  reference  to  the  angular  tools  at 
page  1164;  and  for  these  delicate  tools  the  more  suitable 
arrangement  is  shown  in  fig.  1057,  the  instrument  for  setting 


CONICAL    GRINDERS    FOR    BEAD    TOOLS    AND    DRILLS. 


1172 


bead  tools  and  drills,  which  consists  of  a  miniature  lathe  head, 
mounted  on  a  wooden  table-tee,  having  an  iron  stem  that  fits  the 
socket  of  the  common  lathe  rest.  The  instrument  is  driven  by  a 


FIG.  1057. 


pulley  about  eight  inches  diameter,  screwed  on  the  mandrel  of 
the  turning  lathe,  the  band  from  which  proceeds  to  the  small 
pulley  fixed  in  the  little  mandrel  of  the  instrument,  which  thus 
admits  of  being  driven  at  a  considerable  velocity,  to  compensate 
for  the  small  diameter  of  the  grinders,  figs.  1058 — 9,  which  are 
made  as  a  scries  of  six  brass  and  six  iron  truncated  cones,  each 
a  little  more  than  one  inch  long,  and  gradually  diminishing  in 
size  from  the'  largest,  which  measures  about  five-eighths  of  an 
inch  diameter,  to  the  smallest,  which  terminates  in  a  point,  so 
that  the  series  serves  for  all  sizes  of  tools  below  five-eighths  of  an 
inch  wide.  The  cylindrical  stems  of  the  grinders  are  fitted  to  a 
plain  hole  in  the  mandrel  of  the  instrument ;  and  to  ensure  their 

L2 


1173 


CONICAL    GRINDERS    FOR    BEAD    TOOLS    AND    DRILLS. 


rotation,  they  are  provided  with  a  semicylindrical  projection  at 
the  end,  which  slides  into  a  corresponding  notch  in  the  mandrel 
in  the  same  manner  as  in  the  drill  stocks,  figs.  489  and  450, 
Vol.  II.  Indeed,  fig.  1057  is  used  also  as  a  drilling  lathe  ;  and 


FIGS.  1058.  - 


1059. 


1060.  — 


for  this  purpose  it  is  generally  provided  with  an  assortment  o 
piercing  drills  for  small  holes. 

The  obtuse  cone,  fig.  1060  is  used  for  bead  drills  that  are 
sharpened  from  both  sides,  in  order  to  keep  the  edge  central, 
and  give  the  required  degree  of  penetration. 

In  using  the  instrument,  the  tools  to  be  sharpened  are  first 
ground  upon  the  brass  cones,  charged  with  a  little  fine  emery 
powder  and  oil,  and  they  are  afterwards  polished  on  the  soft  iron 
cones,  supplied  with  crocus  and  oil.  To  give  steadiness  during 
the  application  of  the  tools,  the  hand  is  rested  on  the  wooden 
table-tee  to  which  the  instrument  is  fixed.  The  cones  are 
roughened  to  retain  the  powders,  and  the  tools  should  always  be 
applied  with  the  face  towards  the  smaller  ends  of  the  cones. 

Figs.  1061  to  1076,  represent  of  about  twice  their  usual  size, 
some  of  the  varieties  of  drills  used  for  ornamenting  turned 
works.  The  concave  sweeps  of  figs.  1061  to  1071,  are  sharpen 
with  the  instrument  for  setting  bead  tools  and  drills,  and  the 
manner  in  which  the  tools  are  applied  to  the  cones  will  be  suffi- 
ciently obvious  from  an  inspection  of  the  figures.  Figs.  1061 — 2 
is  the  bead  drill  sharpened  from  both  sides,  but  all  the  rest  are 
sharpened  from  the  one  side  only ;  and  it  is  quite  essential  that 
the  cutting  edge  should  be  exactly  in  a  line  with  the  center  of  the 
drilling  instrument,  as,  should  the  edge  be  in  the  least  degree 
out  of  the  center  of  rotation,  the  drill  would  leave  a  small 
portion  of  the  material  projecting  in  the  center,  and  which  would 
spoil  the  appearance  of  the  work  :  these  drills  therefore  require 


SHARPENING    ORNAMENTAL    DRILLS. 


1174 


in  all  cases  to  be  fitted  to  the  particular  instrument  in  which 
they  are  to  be  used.  The  flat  surface  of  the  drill  is  made 
exactly  diametrical,  and  unlike  the  screw  tools  and  moulding 
tools  used  by  hand,  these  drills  do  not  admit  of  being  sharp- 
ened by  rubbing  the  flat  face  on  the  oilstone,  as  such  a  course 
would  remove  the  edge  from  the  line  of  center ;  the  ornamental 
drills  should  therefore  in  all  cases  be  sharpened  upon  the  end 
only.  It  will  also  be  seen  that  with  the  exception  of  the  three 
first,  they  are  made  to  embrace  only  about  the  one-fourth  of  the 
circle,  as  when  the  drills  are  sharpened  with  one  bevil  they  can 


FIGS.  1061.   1062. 


1063. 


1064. 


1065. 


1066. 


1067. 


107J. 


1072. 


1073. 


only  cut  on  the  one  side  of  the  center,  and  if  the  drills  were 
made  to  embrace  the  half  circle,  the  chamfer  of  the  edge  on  the 
second  side  would  be  in  the  wrong  direction  for  cutting,  and 
consequently  it  could  only  rub  against  the  work,  and  impede  the 
action  of  the  drill. 

Figs.  1072  to  1076,  which  have  convex  and  rectilinear  edges 
do  not  admit  of  being  sharpened  by  any  of  the  guide  instruments 
described;  and  the  restoration  of  their  edges  is  effected  with 
small  slips  of  oilstone  delicately  applied  with  the  fingers,  like  a 


1175 


SHARPENING    ORNAMENTAL    DRILLS,    AND    CUTTERS. 


file.  For  reaching  the  square  internal  corners  of  figs.  1074  to 
1076,  the  square  edges  of  the  oilstone  slip  are  kept  keen  by 
r,  bbing  it  upon  a  piece  of  emery  paper. 

Small  straight  metal  bars,  charged  with  fine  flour  emery,  oil- 
stone powder,  or  crocus  and  oil,  are  sometimes  used  for  sharpen- 
ing tools  of  mixed  forms,  such  as  the  above.  These  metal  bars, 


FIGS.  1074.    1075. 


1076. 


1077. 


1078. 


1079. 


like  the  metallic  laps,  retain  their  shapes  longer  without  dete- 
rioration than  the  natural  oilstone  ;  they  are  generally  made  of 
soft  brass,  and  similar  in  shape  to  small  files  of  a  square  or  half 
round  section.  Considerable  practice  is  however  required  to 
sharpen  the  small  ornamental  drills  and  cutters  of  mixed  forms, 
without  losing  the  necessary  accuracy  of  shape. 

The  side  cutters,  fig.  1077,  with  two  quarter  hollows,  are  made 
of  different  radii,  and  used  for  fluting  concave  sweeps,  such  as 
the  foot  of  a  vase,  they  are  ground  on  the  conical  grinders  of 
fig.  1057.  The  bent  cutters,  fig.  1078,  are  also  made  of  various 
radii,  and  are  principally  used  for  small  eccentric  patterns  on 
plane  or  spherical  surfaces,  such  as  the  top  of  a  snuff-box,  or  the 
head  of  a  walking  stick  ;  but  the  bent  cutters,  although  generally 
made  with  angular  edges,  do  not  admit  of  being  ground  on  the 
instrument  for  angular  tools,  fig.  1047,  but  are  sharpened  with 
slips  of  oilstone.  The  tool,  fig.  1079,  is  employed  for  turning  rings 
of  ivory  or  hardwood,  the  two  half-round  hollows  are  made  of 
the  same  size,  and  exactly  opposite  to  each  other,  in  order  that 
when  the  tool  is  fixed  in  the  slide  rest,  the  left  hand  edge  may 
be  used  to  turn  a  bead  on  the  inside  of  a  hollow  tube,  and  which 
constitutes  the  first  half  of  the  ring,  the  second  half  is  com- 
pleted by  applying  the  right  hand  edge  of  the  tool  to  the  outside 


SHARPENING    MOULDING   TOOLS,    ETC.  1176 

of  the  tube,  and  the  rectilinear  action  of  the  slide-rest  ensures  the 
beads  being  opposite  to  each  other.  The  application  of  these 
various  tools  will  however  be  treated  of  in  a  future  volume. 


Many  tools  from  their  complex  forms  or  other  reasons  do  not 
admit  of  being  sharpened  by  the  ordinary  grinding  processes, 
and  it  is  frequently  necessary  to  resort  to  the  file  for  restoring 
their  edges.  Those  tools  that  are  left  only  of  a  moderate  degree 
of  hardness  such  as  the  saws,  brace  bits,  and  some  circular 
cutters  for  wood  and  brass,  may  be  filed  without  having  been 
previously  softened,  other  tools  are  lowered  in  temper  just 
enough  to  admit  of  the  action  of  the  files,  and  still  retain  suffi- 
cient hardness  to  be  tolerably  durable  when  applied  to  their 
work,  but  such  tools  as  cannot  be  ground,  and  yet  are  required 
to  possess  considerable  hardness,  are  softened  prior  to  the  appli- 
cation of  the  file,  and  are  subsequently  rehardened,  which  pro- 
cesses have  been  already  explained  in  the  first  volume  of  this 
work,  but  as  there  mentioned,  the  less  frequently  steel  is  passed 
through  the  fire  the  better,  as  its  brittleness  becomes  thereby 
materially  increased. 

Moulding  tools  used  in  the  sliding  rest  for  turning  do  not  admit 
of  being  sharpened  on  the  flat  surface  of  the  tool,  as  this  method 
would  remove  the  edge  below  the  center  of  the  lathe,  these  tools 
must  therefore  be  sharpened  at  the  end  only,  and  to  do  which  in 
the  most  effective  manner  it  is  necessary  that  they  should  be 
first  softened  and  then  sharpened  with  files,  or  the  revolving 
hob  on  which  they  were  originally  made.  The  edges  of  these 
moulding  tools  may  be  partially  restored  with  slips  of  oilstone, 
or  the  small  straight  metal  grinders  fed  with  fine  emery,  or  still 
better,  with  a  temporary  counterpart  grinder,  made  by  turning 
with  the  tool  itself  a  circular  moulding  on  a  piece  of  boxwood, 
which  may  be  afterwards  charged  with  flour  emery,  and  used  as 
a  grinder  to  restore  the  edges,  by  this  method  however  the  tools 
soon  deteriorate,  as  at  every  sharpening  they  depart  further  from 
the  original  figure. 

The  fixed  moulding  cutters  used  in  the  large  planing  machines 
for  wood,  are  frequently  sharpened  upon  revolving  laps  with 
rounded  edges.  The  tool  is  twisted  about  to  expose  all  parts 
of  the  chamfer  to  the  action  of  the  lap,  and  which  plan  is 


1177  SHARPENING    CUTTING    PUNCHES,    ETC. 

tolerably  manageable  with  tools  for  large  mouldings.  Sometimes 
a  circular  piece  of  oilstone  turned  to  a  round  edge  is  used  for  this 
purpose,  but  the  difficulty  of  obtaining  the  oilstone  in  sufficiently 
large  pieces,  and  the  numerous  hard  and  soft  places  in  the  stone, 
prevent  this  from  being  so  effective  a  tool  as  might  at  first  be 
supposed.  When  the  forms  of  the  moulding  cutters  become 
depreciated,  it  is  tho  better  practice  to  resort  to  the  use  of  the 
file,  as  for  the  small  slide  rest  tools. 

Figured  cutting  punches  for  cloth,  leather,  and  paper,  and 
also  envelope  cutters,  are  sharpened  with  oilstone  slips.  When 
they  are  worn  down  so  as  to  become  thickened  so  much  as  to 
render  the  sharpening  very  tedious,  they  are  sometimes  thinned 
by  grinding  them  on  rounded  laps,  but  it  is  better  that  they 
should  be  softened  and  filed  to  their  original  forms.  Circular 
cutting  punches  such  as  figs.  938  to  94<1,  page  928,  Vol.  II.  are 
softened  and  turned  in  the  lathe;  the  edges  are  sometimes  made 
a  little  keener  by  holding  a  piece  of  oilstone  to  the  chamfer  of 
the  punch  as  it  revolves  in  the  lathe,  and  circular  punches  that 
are  used  in  manufactories  for  cutting  large  quantities  of  gun 
wadding,  are  in  some  cases  sharpened  in  the  lathe  by  a  lap  which 
is  made  to  revolve  against  the  side  of  the  punch,  whilst  the 
latter  also  revolves,  so  as  to  expose  it  equally  to  the  action  of 
the  lap. 

An  instrument  somewhat  analogous  to  the  patent  knife  sharp- 
eners was  invented  by  the  late  Sir  John  Robison  for  setting  the 
edges  of  razors,  penknives,  and  surgeon's  instruments,  and  is 


FIGS.  1080. 


shown  half  size  in  figs.  1080  &  1081,  it  consisted  of  two  barrel 
shaped  agates  mounted  on  pivots,  free  to  revolve  in  an  elastic 
frame  of  sheet  brass,  the  surface  of  the  agates  was  supplied  with 
finely  pulverized  corundum,  emery,  or  oilstone  powder,  the  edge 
of  the  blade  to  be  sharpened  was  passed  with  slight  pressure 
between  the  two  agates,  which  from  their  shape  could  only  be  in 
contact  at  the  central  point,  so  that  both  sides  of  the  edge  were 


SIR  JOHN  ROBISON'S  SHARPENING  INSTRUMENT.  1178 

acted  on  at  the  same  time,  and  if  too  much  pressure  was  applied, 
the  elastic  frame  allowed  the  agates  to  separate,  and  avoid  injury 
to  the  edge  of  the  blade. 

The  sharpening  of  saws  with  files  has  been  already  explained 
in  Vol.  II.  pages  688  to  698,  and  the  appendix,  note  B.  L.  page 
1011  of  the  same  volume  describes  the  application  of  the  grind- 
stone to  the  teeth  of  large  circular  saws. 


CHAPTER  XXXIII, 

THE  FIGURATION  OF  MATERIALS  BY  ABRASION. 


SECT.  I. THE    PRODUCTION    OF    PLANE    SURFACES    BY    ABRASION. 

IN  the  figuration  of  materials  by  abrasion,  the  principal 
dependence  for  the  correctness  of  form,  is  generally  placed  upon 
the  abrasive  tool,  or  grinder,  being  exactly  a  counterpart  of  the 
form  to  be  produced ;  thus  for  plane  surfaces  a  flat  grinder  is 
employed,  for  concave  surfaces  a  convex  grinder,  and  so  on.  In 
numerous  cases  the  grinder  is  made  as  a  revolving  wheel,  figured 
to  the  required  counterpart  form,  either  upon  the  edge,  or  upon 
the  side,  and  the  work  is  simply  held  to  the  grinder  by  hand, 
without  the  assistance  of  any  mechanical  guidance.  In  other 
cases  the  work  is  traversed  on  slides  beneath  revolving  or  reci- 
procating grinders ;  and  in  some  few  instances,  where  great 
accuracy  of  form  is  required,  the  principal  dependence  is  placed 
upon  the  relative  motions  of  the  grinder  and  work,  both  usually 
under  the  control  of  mechanism. 

The  natural  grindstone  is  in  general  only  used  for  the  rough 
preparation  of  the  surfaces,  which  are  afterwards  more  accurately 
figured  with  metal  grinders  supplied  with  abrasive  powders. 
Within  certain  limits,  it  may  be  said  generally,  that  the  greater 
the  accuracy  desired  in  the  surfaces  to  be  produced,  the  harder 
should  be  the  material  of  which  the  grinder  is  composed  ;  while, 
upon  the  other  hand,  the  finer  the  surface,  or  the  higher  the 
desired  polish,  the  softer  should  be  the  material  of  the  grinder. 
These  opposite  qualities  required  in  the  grinder,  combined  with 
other  circumstances,  render  the  attainment  of  very  accurate,  and, 
at  the  same  time,  highly  polished  surfaces,  a  point  of  considerable 
practical  difficulty,  as  will  be  adverted  to  hereafter. 

The  principal  contents  of  the  present  chapter  will  be  divided 
into  four  sections,  relating  respectively  to  the  methods  of 


LAPS    FOR    FLAT    WORKS    IN    METAL.  1180 

grinding  and  polishing  plane  surfaces,  cylindrical  surfaces,  conical 
surfaces,  and  spherical  surfaces.  These  elementary  forms  may 
be  considered  to  include,  by  their  combination,  nearly  every 
figure  required  in  the  mechanical  arts  ;  and  the  concluding 
section  of  the  chapter,  will  be  devoted  to  a  brief  notice  of  the 
practice  of  glass-cutting,  in  which  all  kinds  of  mixed  and  arbi- 
trary forms  are  produced  by  very  simple  apparatus,  under  the 
guidance  of  the  hand  alone. 

The   present   section   will  refer,   first,   to  the  grinding   and 

polishing  of  flat  surfaces  in   hardened   steel,    and   the   metals 

generally,   and  this  will  be  followed   by  a   description  of  the 

i  methods  of  working  stone  and  marble,  materials  that  are  almost 

[exclusively  wrought   by   abrasion,    and  both   the   manual   and 

machine  processes  will  be  noticed,  as  a  general  example  of  the 

production  of  form  by  abrasion.     Plate  and  sheet  glass  will  be 

next  alluded  to,  and  the  section  will  conclude  with  some  account 

of  the  methods  of  grinding  the  more  accurate  plane  surfaces 

required  for  optical  purposes. 


Revolving  laps  of  metal  used  upon  their  flat  sides,  and  supplied 
with   emery    and  water,    are   extensively  employed  by  mecha- 
nicians for  finishing  flat  surfaces  of  small  and  medium  size,  requir- 
ing tolerable  accuracy.      Sometimes  the  lap  is  employed    for 
brass,  iron,  and  soft  steel,  but  more  generally  the  flat  surfaces 
of  works  in  these  metals,  are  wrought  by  the  planing  machine 
or  file,  and  finished  in  the  manner  described  in  the  catalogue  of 
grinding  processes,  pages  1074  to  1076;  and  the  lap  is  prin- 
cipally employed  for  correcting  works  in  hardened  steel,  such  as 
the  broad  flat   surfaces  of  cutting  tools,  the  faces  of  dies,  har- 
!  dened  steel  plates,  and  numerous  other  objects.    All  these  works 
i  are  made  nearly  flat,  either  with  the  grindstone  or  file,  prior  to 
!  their  being  hardened,  as  the  general  accuracy  of  the  forms  may 
!  be  much  quicker  produced  by  these  means ;  and  the  lap  is  chiefly 
i  resorted  to  for  removing  those  slight  distortions  occasioned  in 
I  hardening,  that  are  beyond  the  correction  of  the  hack  hammer, 
described  at  page  247,  Vol.  I ,  and  also  for  giving  a  smooth  and 
finished  surface  to  the  work. 

Sometimes  the  laps  are  made  of  cast-iron,  or  copper,  because 
!  these  hard  metal  laps  longer  retain  their  forms  uninjured ;  but, 


1181  LAPPING    FLAT    WORKS    IN    METAL. 

as  previously  mentioned,  lead  hardened  with  a  little  antimon] 
is  the  metal  generally  used  for  laps  by  mechanicians,  as  the  lea( 
being  yielding,   allows   the   emery  to  become  embedded  in  its 
surface,,  and  consequently  a  smooth  face  can  be  produced  upon 
the  work  with  an  emery,  the  particles  of  which  are  sufficiently 
large  to  cut  rapidly.     Whereas  when  iron  or  copper  laps  are 
employed,   the   emery  can   scarcely  penetrate   the   lap,  but  is 
partially  lost,  and  the  remainder  rolls  over,  and  makes  scratches 
in  the  work  nearly  equal  in  depth  to  the  size  of  the   emery 
powder. 

Laps  not  exceeding  a  few  inches  in  diameter,  used  by  mecha- 
nicians, are  generally  mounted  vertically,  not  upon  the  middle  of 
long  spindles,  after  the  method  of  those  used  for  cutlery,  but 
screwed  as  chucks  upon  the  mandrel  of  a  lathe,  as  shown  in 
fig.  1054.  This  method  is  adopted  in  order  to  avoid  the  inter- 
ference of  the  spindle,  and  render  the  entire  side  of  the  lap 
available  for  works  of  a  moderate  size.  Larger  laps  are  mounted 
to  revolve  horizontally,  somewhat  after  the  manner  shown  in 
fig.  1039,  but  in  much  stronger  frames,  and  generally  driven  by 
steam  power,  as  the  diameter  of  these  horizontal  laps  is  some- 
times as  much  as  five  or  six  feet.  The  varying  velocity  of  the 
surface  of  the  lap,  which  continually  decreases  from  the  periphery 
to  the  center,  is  however  very  objectionable  in  large  laps,  as  it 
renders  the  tool  much  less  effective  near  the  middle,  and  is 
besides  liable  to  cause  the  lap  to  become  conical,  from  being  less 
worn  near  the  center.  To  avoid  these  interferences  as  much  as 
possible,  large  laps  are  in  most  cases  made  as  annular  disks,  cast 
upon  iron  plates  or  wheels,  so  as  to  leave  a  central  aperture  of 
about  one-third  the  extreme  diameter  of  the  lap. 

In  lapping  small  works  the  object,  if  thin,  is  held  between  the 
thumb  and  finger  nail,  and  placed  fairly  in  its  position  on  the  lap 
while  the  latter  is  at  rest ;  the  lap  is  then  put  in  rotation,  and 
the  work  is  held  quite  steady  to  the  face  of  the  lap  with  moderate 
pressure,  and  the  lap  is  stopped  before  the  removal  of  the  work, 
in  order  to  examine  its  progress.  Larger  pieces  that  can  be 
conveniently  held  in  the  fingers  are  applied  to  the  lap  while  it  is 
in  rotation  ;  the  work  is  quickly  placed  in  its  position,  and  the 
pressure  is  steadily  applied  on  the  back  of  the  work  as  near  as 
convenient  to  its  center,  in  order  to  feel  when  it  bears  uniformly 
upon  the  lap  ;  the  work  is  retained  in  its  position  for  a  few 


LAPPING    FLAT    WORKS    IN    METAL.  1182 

seconds,  and  then,  in  order  to  examine  whether  it  has  been  pro- 
perly placed,  the  work  is  lifted  at  once  perpendicularly  from  the 
face  of  the  lap,  and  not  gradually  drawn  off,  as  the  latter  course 
would  be  liable  to  round  off  the  edges  of  the  work.  Should  it 
appear  to  have  been  incorrectly  placed  on  the  lap,  the  work  is 
applied  in  another  position,  but  the  principal  dependance  is 
placed  upon  the  sense  of  feeling,  as  with  a  little  practice  the 
fingers  readily  appreciate  when  the  work  lies  fairly  upon  the 
surface  of  the  lap. 

Thin  works  of  moderate  size  that  are  too  yielding  to  be 
applied  with  the  fingers,  or  those  that  would  become  too  hot  to 
be  conveniently  held,  are  temporarily  fixed  upon  a  thin  piece  of 
wood  by  driving  two  or  three  pins  into  the  wood,  around  the 
edges  of  the  work,  and  very  small  objects  are  sometimes  cemented 
upon  a  small  piece  of  wood.  In  these  cases,  however,  the  flat 
position  of  the  work  upon  the  lap  cannot  be  so  readily  appre- 
ciated as  when  the  work  is  held  directly  in  the  fingers.  Large 
works  may  be  correctly  placed  upon  the  lap  without  difficulty, 
as  their  size  serves  at  once  as  a  guide,  and  prevents  the  general 
accuracy  given  by  the  file  being  accidentally  depreciated. 

When  the  work  is  first  commenced  it  may  with  advantage,  if 
not  very  small,  be  slidden  to  different  parts  of  the  surface  of  the  lap 
to  equalize  the  wear,  but  towards  the  conclusion  the  work  should 
be  held  in  the  one  position,  and  the  uniform  wear  of  the  lap  may 
be  ensured  by  applying  the  work  to  a  different  part  of  the  lap 
every  time  that  it  is  placed  upon  it. 

When  fresh  emery  is  required  on  the  lap  it  should  be  applied 
by  preference  at  the  commencement  of  lapping  the  article,  in 
order  that  the  emery  may  at  first  cut  rapidly,  and  be  gradually 
worn  finer  with  the  progress  of  the  work,  so  as  to  leave  a  smooth 
surface  at  the  conclusion. 

Flat  works  in  steel,  are  sometimes  polished  on  iron  laps  sup- 
plied with  crocus,  but  more  generally,  after  being  lapped  with 
fine  emery,  they  are  smoothed  with  fine  emery  paper  wrapped 
around  a  file  and  moistened  with  oil,  and  the  works  are  lastly 
polished  with  small  rubbers,  as  explained  on  page  1075.  Flat 
works  in  brass  are  finished  as  described  on'page  1039. 

Facets  on  steel  jewellery,  such  as  beads,  studs,  buttons,  the 
ornaments  on  the  hilts  of  dress  swords,  and  similar  objects,  are 
ground  to  form  on  horizontal  laps,  such  as  fig.  1 039,  fed  with 


1183  CUTTING    FACETS    ON    STEEL    JEWELLERY. 

fine  emerv,  and  are  afterwards  polished  after  the  general  method 
of  cutlery. 

The  small  solid  beads  employed  in  common  articles  are  pre- 
pared from  sheets  of  iron  of  suitable  thickness ;  the  plates  are 
first  punched  in  a  fly  press,  with  small  holes  of  the  proper  size  for 
the  passage  of  the  wire,  by  which  the  beads  are  strung,  the  pieces 
of  metal  to  constitute  the  beads  are  then  punched  out  with  a 
circular  punch  a  little  larger  than  the  intended  diameter  of  the 
beads,  and  having  a  small  central  pin  that  fits  into  the  hole  pre- 
viously punched^  in  order  to  ensure  the  latter  being  in  the  center 
of  the  bead.  The  pieces  are  next  fixed  on  a  pointed  steel  wire 
and  rounded  at  each  end  with  a  file.  They  are  then  case- 
hardened  in  bone  dust  enclosed  in  sheet-iron  boxes,  a  layer  of 
bone  dust  and  one  of  beads  being  placed  alternately  until  the 
box  is  filled  ;  the  whole  are  then  case-hardened,  after  the  method 
explained^  page  260,  Vol.  I.  For  cutting  the  facets  the  beads 
are  fixed  singly  on  pointed  steel  wires,  and  applied  to  the  hori- 
zontal lap  supplied  with  emery  and  water;  no  guide  is  employed 
for  these  common  beads,  but  the  wire  is  held  at  the  proper  incli- 
nation, and  twisted  in  the  fingers  to  cut  the  facets  in  succession 
at  the  one  end,  and  the  bead  is  then  inverted  on  the  steel  point 
for  its  completion.  The  scratches  left  by  the  lap  are  removed 
either  in  the  rumble,  or  by  stringing  them  on  wires,  and  applying 
them  to  revolving  wheel  brushes,  fed  with  oil  and  emery  of  various 
degrees  of  fineness;  rottenstone  is  next  employed  in  a  similar 
manner,  and  the  beads  are  finally  polished  by  rubbing  them  h 
the  naked  hand  with  putty  powder  or  crocus. 

Large  hollow  steel  beads  for  the  best  works,  are  raised  froi 
either  the  best  charcoal  iron,  or  decarbonized  cast-steel  plates, 
after  the  general  method  explained  in  Chap.  XIX.,  Vol.  I. 
The  metal  is  punched  out  in  a  fly  press,  first  as  a  concave  disk,  and 
by  alternate  punching  and  annealing  the  sides  are  brought  to  the 
cylindrical  form,  the  bottom  is  then  removed,  and  the  ends  are 
gradually  closed  in  with  punches,  leaving  a  small  hole  at  each 
end  of  the  hollow  sphere ;  the  beads  are  then  roughly  filed  an< 
case-hardened.     The  facets  on  the  large  beads  of  the  best  kin< 
both  hollow  and  solid,  are  sometimes  more  exactly  cut  by  fixing 
them  on  pointed  wires  inserted  in  wooden  handles,  that,  insteac 
of  being  cylindrical,  are  made  as  polygonal  prisms  of  various 
numbers  of  sides,  according  to  the  numbers  of  facets  required  ii 


CUTTING    FACETS    ON    GOLD    AND    SILVER.  1184} 

the  work ;  a  horizontal  wooden  bar  is  placed  at  a  suitable  height 
on  one  side  of  the  lap,  and  the  flat  sides  of  the  handle  are  rested 
in  succession  upon  the  horizontal  bar ;  this  gives  the  correct 
number  of  facets  to  every  bead,  and  the  angle  at  which  they  are 
placed  is  regulated  by  the  height  of  the  bar  and  the  inclination 
of  the  handle.  The  beads  are  lastly  strung  on  wires>  smoothed 
on  wheel  brushes,  and  polished  by  hand  in  the  same  manner  as 
the  small  beads,  but  more  carefully. 

Round  and  oval  studs  are  in  like  manner  punched  as  flat  or 
concave  disks  out  of  decarbonized  sheet  steel,  and  rounded  with 
the  file  ;  but  before  they  are  case-hardened  the  shanks  are 
attached  by  soldering,  and  covered  with  small  lumps  of  clay  to 
prevent  them  from  being  affected  by  the  hardening  process.  For 
cutting  the  facets,  they  are  held  in  small  hand  vices  or  pin  tongs, 
sometimes  inserted  in  polygonal  handles,  and  applied  to  the  lap 
in  the  same  manner  as  the  best  beads.  For  polishing  the  studs, 
they  are  closely  arranged  in  a  flat  block  covered  with  cement, 
that  is  softened  by  heat  to  allow  the  shanks  of  the  studs  to  pene- 
trate. The  whole  surface  is  then  smoothed  with  emery  and 
water,  applied  with  hard  flat  brushes  rubbed  in  all  directions 
either  by  hand  or  machinery ;  after  the  emery,  rottenstone  is 
employed  in  the  same  manner,  and  the  final  lustre  is  given  with 
putty  powder  or  crocus  on  the  hand.  See  Tech.  Repos.  1830, 
p.  275. 

Facets  on  gold  and  silver,  and  the  flat  parts  of  jewellery 
generally,  are  cut  and  polished  on  revolving  wheels  after  the 
same  general  method  as  that  pursued  by  the  lapidary  for  cutting 
facets  on  stones,  but  the  gold  cutters  commonly  use  vertical  laps 
mounted  much  after  the  fashion  of  fig.  1030,  in  order  that  they 
may  use  both  the  side  and  the  edge  of  the  lap  for  different  parts 
of  the  work.  The  laps  are  made  of  pewter,  or  an  alloy  of  tin 
and  zinc  of  different  degrees  of  hardness  according  to  the  size  of 
the  work.  They  are  turned  very  true  and  flat  on  their  surfaces 
with  the  sliding  rest,  and  left  quite  smooth. 

For  cutting  the  facets  the  laps  are  charged  with  fine  washed 
emery,  smoothed  with  an  agate  or  pebble  burnisher,  and  supplied 
with  water.  The  work  when  too  small  to  be  held  in  the  fingers 
is  cemented  on  a  small  wooden  stick  to  serve  as  the  handle,  and 
the  position  of  the  facets  is  given  with  the  fingers  unassisted  by 
any  guide.  If  the  facets  have  to  be  entirely  produced  by  grinding, 


1187  GRINDING    LARGE    FLAT    WORKS    IN    IRON. 

the  pin,  and  while  the  mandrel  is  rotated,  the  grinder  is  swung 
backwards  and  forwards  in  an  arc  of  about  one  fourth  of  a 
circle.  The  face  of  the  grinder  being  quite  flat,  and  traversed  at 
right  angles  to  the  mandrel,  the  heads  of  the  screws  are  ground 
quite  flat,  notwithstanding  that  they  are  polished  very  highly. 

Sometimes  instead  of  the  mandrel  being  rotated  by  the  flat 
hand  as  above  described,  the  instrument  has  a  pulley  like 
drilling  lathe,  and  is  driven  with  a  drill  bow  ;  in  this  case  one 
mandrel  only  is  used,  and  the  screws  are  fixed  in  similar  grasping 
apparatus  made  as  small  chucks,  fitted  to  the  mandrel  either  by 
a  screw  or  a  plain  conical  fitting. 

Large  flat  works  in  cast  iron  for  heavy  machinery  are 
almost  all  cases  wrought  in  the  planing  machine,  and  when  the 
are  smoothed  it  is  done  with  files  and  rubbers  as  explained  o 
page  1074.  Large  flat  works  in  wrought  iron  are  frequent! 
ground  on  the  edges  of  large  stones  and  finished  with  files.  The 
flat  parts  of  objects  of  complex  form  are  worked  in  the  various 
cutting  and  paring  machines,  and  the  grindstone  is  seldom 
resorted  to  for  plane  surfaces  requiring  even  moderate  accuracy. 
Sometimes  however  when  a  large  surface  has  to  be  made  toler- 
ably level  and  smooth  for  appearance  alone,  the  flat  side  of  the 
grindstone  is  employed,  and  the  work  is  traversed  across  the 
stone  upon  slides;  this  method  of  using  the  flat  side  of  the  stone 
is  however  liable  to  the  objections  stated  on  page  1135. 

In  a  grinding  machine  constructed  by  Mr.  James  Nasmyt 
and  shown  in  figs.  1084  and  1085,*  this  difficulty  is  removed  b 
making  the  grindstone  as  an  annulus  about  fifteen  inches  wid 
composed  of  12  segments  of  stone  each  fitted  into  a  separat 
radial  compartment  in  a  cast  iron  wheel  or  chuck  about  sever* 
feet  diameter.  The  machine  is  double  or  possesses  two  com- 
pound grinding  stones  fixed  on  the  opposite  ends  of  the  same 
shaft,  each  of  the  grindstones  is  provided  with  separate  slides, 
which  are  duplicates  of  each  other,  and  made  self-acting.  The 
foundation  of  the  machine  is  of  masonry,  and  pits  are  sunk  on 
each  side  for  the  lower  part  of  the  stones  to  'work  in,  just  th 
same  as  for  ordinary  large  grindstones.  To  the  masonry 
firmly  fixed  two  cast  iron  frames  #,  or,  upon  which  are  bolte 
two  plummer  blocks  for  carrying  the  main  shaft,  having  at  eac 

*  Transcribed  from  plate  54  of  "Buchanan's  Mill  Work"  by  Rennie,  1841 


:ll 

I 

te 


NASMYTHS    GRINDING    MACHINE    FOR    PLAT    SURFACES.         J  188 

extremity  the  large  wheels  or  chucks,  each  made  as  a  face  plate 
7  feet  diameter,  having  on  the  one  side  12  radial  ribs  about  6 
inches  deep,  that  extend  from  the  center  to  the  periphery  where 
they  terminate  in  a  ring  of  equal  depth.  A  second  concentric 


ring  about  4  feet  diameter  intersects  the  ribs,  and  thus  divides 
the  entire  chuck  into  24  compartments,  in  the  12  outer  of  which 
separate  pieces  of  grindstone  s,  s,  about  14  inches  thick  are  fitted 


like  the  stones  of  an  arch,  and  each  is  wedged  fast  between  the 
ribs  by  a  single  set  screw  passing  through  the  outer  rim  of  the 
chuck.  On  the  top  of  the  cross  frames  a,  are  fixed  two  longitu- 


M    2 


1189       NASMYTHS    GRINDING    MACHINE    FOR    FLAT    SURFACES. 

dinal  frames  b,  #,  for  supporting  the  bearers  c,  c,  upon  which 
the  slides  dy  are  traversed  across  the  faces  of  the  stories.  Upon 
the  slides  d,  are  mounted  at  right  angles  the  slides  e>  upon  which 
the  work  is  fixed  and  advanced  towards  the  stone  as  the  grind- 
ing proceeds. 

A  self-acting  motion  is  given  to  the  slide  d,  by  which  the 
work  being  faced  is  gradually  traversed  along  the  bearers  c,  so 
as  to  bring  the  face  of  the  work  in  contact  with  the  revolving 
grindstones.  This  motion  is  obtained  as  follows.  Upon  the 
main  shaft  of  the  machine  is  fixed  an  endless  screw,  which  drives 
a  worm  wheel  fixed  on  an  upright  spindle,  communicating  bv 
two  pairs  of  bevil  wheels  and  a  short  horizontal  spindle,  with  a 
second  horizontal  spindle  running  the  whole  length  of  the 
machine,  and  having  at  each  extremity  a  small  bevil  wheel,  that 
leads  alternately  into  two  other  bevil  wheels  fitted  loosely  on  the 
screw  of  the  slide  d,  which  is  traversed  in  opposite  directions, 
accordingly  as  the  one  or  other  wheel  is  engaged  by  a  central 
clutch  seen  at  /. 

The  clutch  is  shifted  for  every  traverse  of  the  slide  </,  by 
means  of  a  rod  sliding  endlong  through  two  bearings  fixed  on 
the  front  of  the  bearers  c ;  and  upon  this  rod  two  pins  are 
fitted  that  admit  of  being  adjusted  to  any  distance  from  each 
other,  according  to  the  length  of  traverse  required  for  the  work 
in  hand.  A  pin  fixed  on  the  slide  d,  is  brought  by  the  traverse 
of  the  machine  in  contact  with  one  of  the  pins  on  the  rod,  and 
slides  it  endlong,  so  as  to  disengage  the  clutch  from  the  one 
bevil  wheel  on  the  screw  of  the  slide  d,  and  cause  it  to  take  into 
the  other  and  reverse  the  motion ;  a  counterpoise  weight  g  is 
fixed  on  the  rod  to  retain  it  steady  while  the  clutch  is  being 
shifted.  The  upper  slide  e,  is  also  provided  with  a  screw  for 
advancing  the  work  towards  the  stone  in  steps,  as  each  layer  is 
ground  off  by  the  traverse  motion. 


The  softer  varieties  of  stone  such  as  Bath,  Caen,  and  Pens- 
wick  stones,  admit  of  being  cut  into  slabs  and  smaller  pieces  with 
toothed  saws,  which  are  sometimes  made  of  a  similar  form  to  the 
cross  cutting  saws  for  wood  with  upright  teeth,  shown  in  figs. 
640  and  643,  Vol.  II.,  but  the  toothed  saws  for  soft  stone  are 
generally  made  somewhat  wider  in  the  middle  than  those  for 


SAWING    SOFT    STONE,  SLATE,  ETC/  1190 

wood,  so  as  to  make  the  blade  more  rounding  in  the  direction  of 
its  length,  and  instead  of  being  reciprocated  backwards  and  for- 
wards nearly  in  a  horizontal  line,  as  for  cross  cutting  wood,  the 
toothed  saws  for  stone  are  used  with  a  swinging  stroke,  so  as  to 
act  upon  only  a  moderate  portion  of  the  length  of  the  cut  at  the 
one  instant  of  time  ;  this  is  done  to  reduce  the  labour  and  give 
the  saw  teeth  more  penetration.  Some  of  these  very  soft  stones 
are  worked  with  chisels  and  gouges  similar  to  those  of  the  car- 
penter, and  they  may  even  be  worked  into  mouldings  with 
planes  like  those  used  for  hardwood,  but  this  is  not  generally 
practised. 

Slate  as  mentioned  at  page  165  of  Vol.  I.  is  sawn  and  some- 
times planed  with  cutting  tools  very  similar  to  those  used  for 
wood,  except  that  they  are  stronger  and  are  applied  by 
machinery,  the  action  being  partly  cutting,  and  partly  forcing 
off  the  flakes  of  slate,  as  if  the  tools  are  allowed  merely  to  scrape 
over  the  surface  their  edges  become  rapidly  worn  away.  But  the 
various  sandstones,  limestones  and  marbles  are  too  compact  to 
be  thus  treated,  and  they  are  consequently  worked  almost  exclu- 
sively by  the  chipping  chisel  and  various  abrasive  processes ;  the 
chisel  being  used  for  such  parts  of  the  material  as  are  in  excess, 
as  in  sculptured  works,  and  the  abrasive  processes  being 
employed  for  dividing  the  blocks  into  slabs  and  small  pieces, 
which  are  subsequently  ground  to  the  required  forms  with  sand 
and  water.  In  the  case  of  marble  the  pieces  are  finally  polished 
with  abrasive  powders  applied  on  rubbers  of  various  materials  as 
mentioned  at  pages  1076  to  1078  of  the  present  volume. 

The  ordinary  saw  used  for  dividing  blocks  of  stone  and  marble 
into  flat  slabs,  is  shown  in  figure  1086.  It  consists  of  a  parallel 
blade  of  soft  iron  from  5  to  10  feet  long,  from  4  to  5  inches 
wide,  and  from  one-eighth  to  one-sixth  of  an  inch  thick,  the 
blade  is  perforated  near  each  end  with  a  hole  about  three 
I  quarters  of  an  inch  diameter,  for  the  reception  of  an  iron  pin,  by 
;  which  the  saw  is  strained  in  a  rectangular  wooden  frame.  The 
jblade  is  inserted  in  the  saw  kerfs  in  the  upright  sides  of  the 
]  frame,  called  the  heads,  and  the  pins  rest  in  two  notches  near 
the  lower  extremities  of  the  heads,  which  serve  as  the  handles  of 
i  the  saw,  and  are  kept  distended  by  the  wooden  stretcher  called 
t  the  pole,  placed  about  a  foot  from  the  upper  ends  of  the  heads,  and 
I  rested  at  each  end  against  a  loose  block  of  wood  called  the  bolster. 


1191 


SAW    FOR    STONE    AND    MARBLE. 


Instead  of  a  coil  of  string  twisted  with  a  short  lever  bein| 
employed  for  drawing  the  upper  ends  of  the  frame  together, 


FIG.  1086. 


in  the  saws  for  wood,  this  object  is  effected  by  the  use  of  a  kind 
of  chain  made  of  looped  iron  rods,  with  intermediate  C-shaped 
links,  for  adjusting  the  total  length  of  the  chain,  which  is  fur- 
nished with  iron  loops  that  embrace  the  upper  ends  of  the 
heads.  The  tension  is  given  by  a  right  and  left  hand  screw 
fitted  to  two  looped  nuts,  attached  to  the  iron  rod  by  C  links, 
the  double  screw  has  holes  for  a  lever,  by  which  it  is  twisted  so 
as  to  draw  the  upper  ends  of  the  heads  of  the  frame  together 
with  great  force,  and  thereby  stretch  the  saw  in  a  most 
effectual  manner.  The  top  view  of  the  tightening  apparatus  is 
shown  separately  at  a. 

The  depth  to  which  the  saw  can  penetrate,  is  limited  by  the 
distance  from  the  edge  of  the  blade  to  the  under  side  of  the 
pole,  the  nearer  the  pole  is  to  the  saw  the  greater  is  the  stability 
of  the  blade,  and  all  the  parts  of  the  frame  are  made  detached, 
so  as  to  allow  of  their  being  combined  and  adjusted  to  suit  the 
different  sizes  of  blocks  of  stone.  The  same  pair  of  heads  are 
used  with  poles  and  saws  of  various  lengths,  and  the  pole  is 
placed  at  different  heights  from  the  blade,  according  to  the 
depths  of  the  blocks  of  stone.  When  the  latter  are  very  deep, 
a  longer  pair  of  heads  are  substituted,  but  long  heads  are 
avoided  as  much  as  possible,  as  the  stability  of  the  saw  frame  is 
thereby  much  reduced. 

The  blade  of  the  stone-saw,  like  the  metal-laps  used  for  grind- 


SAW    FOR    STONE,  AND    MARBLE,  ETC.  1192 

ing  generally,  does  not  itself  cut  the  stone,  but  simply  serves  as 
the  vehicle  for  the  application  of  the  sand,  which  acts  as  the 
teeth  of  the  saw,  and  performs  the  cutting  process.  The  coarse- 
ness of  the  sand  that  is  employed  depends  upon  the  hardness  of 
the  stone  to  be  cut,  for  moderately  soft  stone  a  coarse  sharp 
sand  is  employed,  and  for  the  harder  varieties  of  marble  a  fine 
sand  is  used ;  the  sand  or  grit  generally  employed  in  London  for 
cutting  stone  is  obtained  from  the  scrapings  of  roads  paved  with 
flint.  The  scrapings  are  sifted  and  washed  through  perforated 
copper  sieves,  much  the  same  as  emery,  as  it  is  of  great  import- 
ance that  the  sand  should  be  clean  and  quite  free  from  small 
pieces  of  stone,  or  any  other  extraneous  matters.  Should  a 
small  piece  of  wood  or  a  bit  of  coarse  gravel  by  any  accident  get 
into  the  kerf  beneath  the  saw  blade,  the  little  piece  would  roll 
over  backwards  and  forwards,  and  materially  impede  the  cutting 
of  the  block,  and  it  then  becomes  necessary  to  remove  the  saw 
and  wash  away  the  obstacle,  by  pouring  water  down  the  saw 
kerf. 

The  cutting  action  of  the  sand  is  assisted  by  a  small  stream 
of  water,  supplied  from  a  barrel  placed  a  little  above  the  block 
of  stone.  A  small  hole  is  made  near  the  bottom  of  the  barrel, 
to  which  is  fitted  a  spigot  and  faucit,  or  more  commonly  a  loose 
wooden  peg  grooved  up  the  one  side,  which  allows  of  the  escape 
of  a  minute  stream  of  water,  that  trickles  down  a  sloping  board 
placed  so  as  to  lead  the  water  into  the  saw  kerf.  A  little  heap  of 
sand  is  placed  near  the  path  of  the  water,  and  the  workman  is 
provided  with  a  wooden  stick  with  an  iron  hook  at  the  end,  or 
more  commonly  an  old  knife  blade  placed  at  right  angles  to  the 
stick  near  its  end.  This  tool  is  called  a  drip  stick,  and  is  used 
occasionally  to  draw  forward  a  small  quantity  of  sand  into  the 
running  water,  which  thus  carries  down  the  necessary  supply  of 
sand  for  the  cut,  and  the  water  flows  away  at  the  ends  of  the 
kerf;  carrying  with  it  the  worn-out  sand  and  the  particles  of 
stone  removed  in  the  cutting ;  the  drip  stick  is  also  used  for 
tapping  the  wooden  peg,  so  as  to  increase  or  diminish  the  flow  of 
water  according  to  circumstances. 

The  weight  of  the  saw  and  frame  supplies  the  necessary 
pressure  for  causing  the  penetration  of  the  sand,  so  that  the 
workman  has  only  to  guide  the  saw,  and  push  it  backwards  and 
forwards  for  the  cut,  and  when  the  pressure  is  so  great  as  to 


1193  MARKING    OUT   BLOCKS    OF    STONE    AND    MARBLE. 

render  the  work  too  laborious,  a  counterpoise  weight  is  hung 
from  a  pulley  placed  over  the  saw  frame,  to  which  a  cord  is 
attached,  so  as  to  reduce  the  pressure  to  the  required  amount. 
Under  this  arrangement  the  saw  works  more  easily,  but  it  does 
not  cut  so  rapidly. 

For  marking  upon  the  block  of  stone  or  marble  the  lines 
upon  which  it  is  to  be  sawn,  as  for  cutting  it  into  slabs  of  one  or 
two  inches  thickness,  the  block  is  first  shifted  upon  rollers  into 
the  position  in  which  it  is  to  be  sawn  ;  it  is  then  mounted  upon 
square  pieces  of  wood  called  skids,  with  that  side  of  the  block 
upwards  which  is  to  constitute  the  edges  of  the  desired  slabs, 
and  as  the  blocks  are  frequently  of  very  irregular  forms,  it  is 
necessary  to  make  one  line  around  the  top,  and  two  ends  of  the 
block,  to  serve  as  the  basis  from  which  the  other  lines  are  set 
off,  much  the  same  as  in  setting  out  round  timber  described  in 
pages  703  to  707  of  Vol.  II. 

The  position  of  the  first  line  having  been  determined,  so  as  to 
allow  of  the  greatest  number  of  parallel  slabs  being  cut  from  the 
block,  two  marks  are  made  on  the  top  of  the  stone  close  to  the 
ends,  with  a  piece  of  soft  black  slate  found  amongst  coal,  and 
called  Uack^  a  line  is  then  drawn  under  the  guidance  of  a  straight 
edge  to  connect  these  two  marks,  and  the  line  is  continued  down 
one  end,  also  with  the  straight  edge.  An  equal  distance  is  then 
set  off  at  the  bottom  of  the  opposite  end,  and  a  line  is  drawn  to 
serve  as  a  temporary  guide ;  two  straight  edges,  each  from  two  to 
three  feet  longer  than  the  depth  of  the  block,  are  applied  to  the 
two  end  lines,  and  the  workman  looks  along  the  line  of  the  two 
straight  edges,  to  see  whether  they  are  parallel  to  each  other,  or 
out  of  winding,  in  much  the  same  manner  as  in  the  application 
of  the  winding  sticks  to  narrow  works  in  wood,  explained  at 
page  500  of  Vol.  II.,  except  that  for  setting  out  the  blocks  of 
stone,  the  straight  edges  are  placed  perpendicular  instead  of 
horizontal.  Should  the  straight  edges  not  appear  parallel  to 
each  other,  the  one  at  tjie  second  end  of  the  stone  is  shifted  at 
the  bottom  until  the  two  straight  edges  are  in  one  plane ;  the 
permanent  line  at  the  second  end  of  the  block  is  then  drawn  in 
the  corrected  position  of  the  straight  edge,  and  if  the  work  have 
been  correctly  performed,  all  the  three  lines  will  be  in  the  same 
plane.  The  thicknesses  of  the  required  slabs  are  then  gaged  off 
from  this  foundation  line,  and  the  lines  on  the  top  of  the  stone 


SAWING    STONE    AND    MARBLE.  1194 

are  chased,  or  cut  in  about  one-eighth  of  an  inch  deep  with  a 
narrow  chisel,  to  form  a  groove  in  which  the  edge  of  the  saw  is 
placed  for  the  commencement  of  the  cut.  The  end  lines  are  also 
chased,  as  the  water  and  sand  would  wash  out  the  black  lines. 

Before  commencing  the  sawing,  the  workman  examines  with  a 
plumb  line  whether  the  end  lines  are  vertical,  and  if  not,  wedges 
are  driven  under  one  side  of  the  block,  to  bring  the  end  lines 
exactly  upright,  the  saw  is  then  inserted  in  the  groove,  and  the 
sawing  is  proceeded  with,  care  being  taken  in  the  first  entry  to 
keep  the  saw  quite  upright,  which  is  greatly  assisted  by  the 
height  of  the  saw  frame.  Should  the  saw  make  the  cut  a  little 
oblique  to  the  lines,  the  position  of  the  saw  is  slightly  twisted  in 
the  saw  kerfs  of  the  wooden  heads,  by  blows  of  a  hammer  applied 
on  one  side  of  the  pins  which  retain  the  blade  in  the  frame,  and 
which  causes  the  saw  to  cut  in  the  reverse  direction.  The  necessity 
for  changing  the  direction  of  the  cut  is,  however,  avoided  as  much 
as  possible,  as  it  makes  the  surface  of  the  slabs  irregular  from  the 
hollows  thus  produced,  and  which  are  called  galls.  The  necessity 
for  grinding  out  these  galls,  much  increases  the  labour  of  producing 
a  flat  surface  on  the  slabs,  and  the  thickness  of  which  is  also 
lessened  ;  this  it  is  sometimes  an  important  object  to  avoid  with 
valuable  marbles,  which  are  occasionally  cut  into  veneers  for 
inlaying,  not  exceeding  one-eighth  of  an  inch  in  thickness. 

The  length  of  the  traverse  of  the  saw  is  generally  about  20 
inches,  and  a  saw  is  therefore  chosen  that  is  about  2  feet  longer 
than  the  block  to  be  cut,  as  the  shorter  the  saw  that  can  be 
efficiently  used,  the  more  firmly  the  blade  is  held.  When  two 
small  blocks  have  to  be  cut,  they  are  frequently  placed  end  to 
end  with  the  intended  cuts  in  the  same  plane ;  and  to  prevent 
the  sand  and  water,  called  the/m7,  from  flowing  out  between  the 
stones,  the  interval  is  filled  up  with  straw  rammed  in  firmly 
between  the  two  blocks;  in  the  case  of  light-coloured  marbles  clean 
shavings  are  used  for  this  purpose,  as  the  straw  would  stain  the 
surfaces,  unless  the  slabs  were  washed  immediately  afterwards. 

After  the  marble  has  been  cut  into  slabs  with  the  stone  saw, 
if  it  is  required  to  be  reduced  into  smaller  pieces,  or  narrow  slips, 
such  as  shelves,  or  the  sides  of  chimney-pieces,  the  slab  is  laid  on 
a  bench,  having  a  flat  surface  of  hard  stone,  or  marble,  called  a 
rubbing-bed.  The  lines  indicating  the  margins  of  the  required 
pieces  are  marked  with  the  straight  edge,  and  black,  and  the 


1195  GRUB    SAWS    FOR    STONE    AND    MARBLE. 

lines  are  chased  with  a  narrow  chisel,  as  for  the  entry  of  the  stone 
saw,  but  the  cutting  is  effected  with  smaller  blades,  called  grub- 
saws,  shown  in  fig.  1087  ;  they  consist  of  plates  of  iron  from  one- 
twentieth  to  one-tenth  of  an  inch  thick,  from  6  inches  to  4  feet 
long,  and  6  to  8  inches  wide  when  new.  These  blades  are  not 
stretched  in  a  frame,  but  are  stiffened  by  having  their  upper 
edges  clamped  between  two  pieces  of  wood  extending  their  whole 
length,  and  measuring  about  2  inches  wide  and  1  inch  thick,  the 

FIG.  1087. 


whole  being  held  together  by  means  of  ordinary  wood  screws, 
passing  through  holes  in  the  plate,  so  as  to  form  a  wooden  back 
something  like  those  of  the  dovetail  saws,  and  which  serves  as  the 
handle  by  which  the  grub-saw  is  used. 

The  blade  should  always  be  shorter  than  the  length  of  the  cut 
to  be  made,  as  should  the  blade  be  longer  than  the  cut,  it  would 
be  worn  hollow  from  the  greater  amount  of  rubbing  to  which  the 
middle  would  be  exposed ;  but  when  the  grub-saw  is  much 
shorter  than  the  cut,  it  is  liable  to  be  worn  rounding  in  its 
length.  To  counteract  this  tendency,  the  grub-saws  are  some- 
times filed  at  every  4  or  5  inches,  with  angular  notches  about 
f  of  an  inch  deep,  and  which  also  allow  the  feed,  or  the  sand  and 
water,  to  reach  the  bottom  of  the  cut  with  greater  facility,  and 
the  grub-saws  are  consequently  considered  to  cut  rather  faster 
for  the  notches. 

The  width  of  the  iron  blade  measured  to  the  wooden  back,  limits 
the  depth  of  the  cut  to  which  the  grub-saw  can  be  applied,  and 
in  selecting  a  saw  for  any  particular  piece  of  stone,  preference  is 
given  to  as  narrow  a  blade  as  can  be  fairly  applied  to  that  thick- 
ness, as  when  the  blade  is  wide,  it  is  rather  feeble  sideways,  and 
it  is  besides  more  liable  to  be  twisted  from  the  perpendicular, 
when  rubbed  backwards  and  forwards  in  the  cut,  with  one  or 
both  hands  applied  on  the  back  of  the  saw  near  the  middle  of  its 
length. 

Slabs  of  marble  or  stone  that  are  required  to  have  flat  surfaces, 


GRINDER    FOR    PLANE    SURFACES    IN    STONE    AND    MARBLE.         1196 

after  having  been  sawn  to  their  respective  sizes  are  laid  upon 
the  rubbing-bed,  with  that  side  upwards  which  is  to  be  ground 
flat,  a  smaller  slab  of  stone,  with  a  tolerably  flat  surface,  is 
then  selected  to  be  used  with  sand  and  water  as  the  grinder,  the 
size  of  the  grinder  or,  as  it  is  called,  the  runner,  depends  upon  the 
size  and  condition  of  the  work  to  be  ground ;  if  the  slab  be  large 
and  moderately  well  sawn,  as  large  and  heavy  a  runner  is  used  as 
the  workman  can  conveniently  push  backwards  and  forwards  ;  if 
the  work  be  rounding  in  the  middle,  a  smaller  runner  is  employed; 
and  if  the  slab  be  hollow  in  the  direction  of  its  length,  a  long 
narrow  runner  is  used,  the  selection  depending  upon  the  condition 
of  the  slab,  and  the  judgment  of  the  workman. 

The  kind  of  stone  which  is  used  for  the  runner  is  partly 
dependent  upon  the  kind  of  stone  to  be  ground,  but,  generally 
speaking,  the  runner  should  be  the  harder  stone ;  indeed,  two 
soft  stones,  such  as  Portland,  if  ground  together  would  hang  to 
each  other  to  such  an  extent  as  very  materially  to  increase  the 
labour  of  grinding.  Portland  stone  is  therefore  generally  ground 
with  a  runner  of  York  stone.  York  stone  and  marble  are 
ground  with  runners  of  the  same  material  as  the  slab,  but  it  is 
better  that  the  runner  should  be  of  a  harder  variety. 

The  stone  used  as  the  runner  becomes  itself  ground  flat  in  the 
process,  and  advantage  is  taken  of  this  circumstance  to  grind 
slabs  of  moderate  size,  by  using  them  as  runners  for  larger  slabs, 
the  two  stones  being  ground  flat  just  as  readily  as  one. 

Sometimes  iron  rubbers  or  runners  are  employed,  and  these 
have  the  advantage  of  retaining  a  much  greater  accuracy  of 
form ;  they  are  far  more  durable,  and  the  sand  and  water  can 
be  applied  in  a  more  regular  manner,  as  the  iron  runners  are 
frequently  made  with  a  raised  rim  around  their  upper  surface, 
as  to  form  a  kind  of  tray,  within  which  the  mixed  sand  and 
rater  is  placed,  and  the  flat  surface  constituting  the  bottom  of 
the  tray  is  perforated  with  holes,  through  which  a  constant  supply 
of  sand  and  water  is  admitted  to  the  grinding  surfaces. 

Of  whichsoever  material  the  runner  may  consist,  it  is  provided 
with  a  handle  of  sufficient  length  to  enable  the  workman  to 
traverse  it  over  the  entire  surface  of  the  slab;  if  the  runner  be 
large  and  of  stone  it  is  in  general  held  as  in  fig.  1088,  the  end  of 
the  long  handle  is  nailed  on  the  upper  side  of  a  board  about 
1  foot  long  and  9  inches  wide,  having  a  slip  of  wood  about 


1197         GRINDING    PLANE    SURFACES    IN    STONE    AND    MARBLE. 

2  inches  wide  nailed  on  the  under  surface,  to  rest  against  the 
one  end  of  the  runner,  which  is  retained  at  the  other  end  by  a 
loose  iron  ring  about  1J  inch  wide  provided  with  a  tail-piece.  The 


FIG.  1088. 


loose  ring  called  the  hook  is  slipped  up  the  handle  until  the  tail- 
piece is  stopped  by  the  stone,  when  from  the  angular  position 
assumed  by  the  loose  ring  its  edges  slightly  penetrate  the  handle 
and  prevent  its  return,  the  runner  is  thus  securely  grasped 
between  the  wooden  stop  and  the  iron  tail-piece.  If  the  runner 
be  of  iron,  the  handle  is  generally  passed  through  two  holes  cast 
in  the  projecting  ends  of  the  runner,  or  otherwise  two  upright 
pieces  are  cast  on  the  back  for  the  reception  of  the  handle. 
For  small  runners  the  handle  is  sometimes  fixed  at  an  angle,  and 
sometimes  vertical,  as  mentioned  at  page  1089  under  the  head 
RUBBER,  Article  2. 

In  grinding  the  flat  surface  of  a  marble  or  stone  slab,  the 
runner  plentifully  supplied  with  sharp  sand  and  water,  is  pushed 
backwards  and  forwards  in  all  directions  over  the  face  of  the 
slab,  the  flatness  of  which  is  frequently  examined  with  a  straight 
edge  applied  in  all  positions  upon  the  surface  of  the  slab,  but 
principally  upon  the  four  margins  and  the  two  diagonals  of  the 
stone,  and  as  the  slab  approaches  a  flat  surface  the  sand  is 
gradually  changed  for  finer  kinds,  according  to  the  quality  of  the 
surface  required  on  the  stone  :  for  marble,  the  last  process  of 
smoothing  prior  to  the  commencement  of  polishing  is  in  London 
effected  with  silver  sand,  which  is  generally  obtained  from  the 
neighbourhood  of  Croydon.  The  smoothing  should  be  continued 
until  all  the  marks  made  by  the  saw  and  the  coarser  sand  are 


GRINDING    PLANE    SURFACES    IN    STONE    AND    MARBLE.          119S 

entirely  removed,  and  the  slab  presents  a  uniformly  smooth 
surface,  the  last  marks  to  be  eradicated  in  the  smoothing  are 
generally  those  called  stuns,  made  in  sawing  the  marble  by  coarse 
particles  of  sand  getting  between  the  side  of  the  saw  blade  and 
the  saw  kerf,  and  which  are  sometimes  forcibly  driven  into  the 
surface  of  the  marble,  and  cause  specks  that  unless  removed 
greatly  impair  the  appearance  of  the  work  when  polished. 

Single  pieces  of  marble  of  a  moderate  size  and  weight,  say  not 
exceeding  18  inches  square  and  1  inch  thick,  are  ground  by  laying 
them  face  downwards  upon  a  slab  supplied  with  sand  and  water, 
the  marble  to  be  ground  is  rubbed  by  the  hands  in  all  directions 
over  the  slab,  but  chiefly  in  the  form  of  a  figure  of  8,  to  insure  its 
being  ground  equally,  the  path  in  which  the  marble  is  rubbed 
being  occasionally  reversed. 

When  several  small  pieces  of  marble  have  to  be  ground  flat, 
such  as  the  squares  for  a  tesselated  pavement,  it  would  be  very 
tedious  to  grind  them  separately,  they  are  therefore  arranged 
close  together  and  face  downwards  upon  a  large  flat  stone. 
Plaster  of  Paris  is  then  poured  over  their  upper  surfaces,  and  a 
long  stone  a  little  narrower  than  the  width  of  the  pieces  called 
a  liner  is  laid  over  the  whole,  which  thus  become  cemented 
together  with  all  their  faces  level,  notwithstanding  that  they 
may  be  of  irregular  thicknesses.  The  whole  are  then  ground 
together  as  a  runner  upon  a  slab  of  marble,  and  the  liner  being 
narrower  than  the  squares,  allows  of  the  two  edges  being  ground 
as  explained  in  the  next  paragraph. 

For  grinding  the  edges  of  marble,  large  slabs  are  propped 
upright  against  some  temporary  support,  and  narrow  rubbers  of 
stone  or  iron  supplied  with  sand  and  water  are  applied  to  the 
edges.  Narrow  pieces  such  as  shelves  are  placed  edgeways  upon 
flat  slabs,  and  rubbed  lengthways  by  one  or  two  men. 

After  the  smoothing  with  silver  sand,  marble  works  are 
rubbed  with  pieces  of  first  and  second  gritstone,  sometimes  with 
pumice-stone,  but  which  is  not  generally  used  on  account  of  the 
expense,  and  the  grounding  is  completed  with  pieces  of  snake- 
stone,  as  mentioned  on  page  1076.  The  pieces  of  gritstone  and 
snakestone  are  not  laid  flat  upon  the  work,  but  placed  edgeways 
at  an  angle  of  about  50  degrees,  and  rubbed  in  the  direction  of 
their  breadth,  much  the  same  as  in  sharpening  a  plane  iron  or 
chisel.  Flat  surfaces  in  marble  are  lastly  polished  with  the 


1199 


WORKING    MOULDINGS    IN    STONE    AND    MARBLE. 


block,  or  wooden  rubber  covered  with  thick  felt,  described  on 
page  1089,  article  3,  and  shown  in  fig.  1089.    A  piece  of  stone 


FIG.  1089. 


nearly  as  large  as  the  block  is  generally  placed  upon  it  as  a 
weight,  and  the  block  is  rubbed  backwards  and  forwards.  The 
proper  succession  of  polishing  powders  is  mentioned  at  page 
1076,  under  the  head  MARBLE,  but  it  should  be  observed  that 
crocus  is  only  applied  upon  dark-coloured  marbles,  as  light- 
coloured  or  statuary  marbles  would  be  stained  by  the  crocus,  and 
for  the  last  finish  the  London  workmen  prefer  coarse  linen  rags. 

Mouldings  in  stone  and  marble,  are  worked  partly  by  the 
chipping  chisel  and  partly  by  grinding.  The  drawing  of  the 
required  moulding  is  first  pricked  through  upon  a  piece  of  card- 
board, which  is  then  cut  out  to  the  counterpart  form  of  the 
moulding,  and  if  it  be  small  a  copy  is  made  in  sheet  metal,  gene- 
rally zinc  is  used  for  the  purpose,  as  it  is  easily  filed,  and  a 
tolerably  cheap  material,  these  counterparts  made  in  metal  for 
small  mouldings  are  called  moulds,  those  counterparts  made  in 
wood  for  large  mouldings  are  known  as  templates,  but  they  arc 
both  applied  in  exactly  the  same  manner. 

The  outline  of  the  moulding  is  first  scribed  from  the  mould 
upon  the  two  ends  of  the  block  of  stone,  and  if  the  moulding  is 
deep  so  that  any  considerable  portions  have  to  be  removed, 
of  either  a  soft  stone  that  is  easily  sawn,  such  as  Caen  stone,  or 
of  any  valuable  marble,  such  as  statuary  marble,  the  large  pieces 
are  removed,  either  with  toothed  saws  or  grub-saws,  according 
to  the  hardness  of  the  material.  If  however  the  stone  is  hard 
and  not  of  great  value,  the  principal  portion  is  chipped  away  in 
large  chamfers ;  lines  are  then  drawn  on  the  face  of  the  work,  to 


WORKING    MOULDINGS    IN    STONE    AND    MARBLE.  1200 

denote  the  several  parts  of  the  mouldings,  which  parts  are 
worked  first  as  square  fillets  and  small  chamfers.  The  contour  of 
the  moulding  is  then  formed  with  small  straight  and  round- 
ended  chipping  chisels,  under  the  guidance  of  the  mould,  and  the 
lines  on  the  ends  of  the  block,  the  quirks  of  the  beads  and  similar 
parts  are  cut  in  with  grub-saws  of  suitable  thicknesses. 

When  the  mouldings  have  been  rendered  as  perfect  as  admis- 
sible with  the  chisels,  their  surfaces  are  completed  by  grinding, 
which  is  done  with  stone  or  iron  rubbers,  having  concave-  and 
convex  edges  for  the  curved  parts,  and  square  edges  for  the  fillets 
and  flat  surfaces,  sand  of  various  degrees  of  fineness  being  used, 
according  to  the  progress  of  the  work. 

The  square  iron  rubbers  for  the  fillets  and  square  edges  are 
made  of  bars  of  iron  about  1  inch  deep  of  various  widths  and 
from  1  to  3  feet  long  according  to  the  length  of  the  work,  the 
bar  is  thinned  and  turned  up  at  each  end  for  its  attachment  to 
the  wooden  stock  upon  which  it  is  mounted  as  shown  in  fig.  1090. 

FIG.  1090. 


Small  rubbers  entirely  of  iron  and  from  2  to  10  inches  long  are 
used  for  these  parts  of  mouldings  which  are  of  frequent  occur- 
rence, such  as  beads  and  astragals,  but  for  the  less  frequent  parts 
of  mouldings,  stone  rubbers  are  principally  employed,  from 
motives  -of  economy. 

The  mouldings  are  finally  smoothed  and  polished  with  small 
slips  of  gritstone  and  snake  stone,  followed  by  putty  powder 
applied  on  the  ends  of  soft  deal  sticks,  they  are  afterwards, 
clouted  up  or  rubbed  with  pieces  of  nearly  worn-out  felt,  removed 
from  the  blocks  used  for  polishing  flat  surfaces,  and  the  last 
finish  is  given  with  linen  rags  and  putty  powder.* 

*  Polished  marble  that  has  become  soiled  is  best  cleaned  with  a  weak  lye  made 
of  pearl  ash  and  a  little  soft  soap,  and  which  may  also  be  employed  to  clean 
alabaster  that  is  only  moderately  soiled.  This  method  has  the  advantage  of  not 
removing  the  polish  like  the  more  effectual  method  described  on  page  1035  of  the 
Catalogue  Article  4. 

Muriatic  acid  is  sometimes  used  for  cleaning  marble  but  it  is  ruinous  to  delicate 


1201  INLAID    WORKS    IN    MARBLE. 

Inlaid  works  in  coloured  marbles  such  as  mosaic  and  other 
patterns  inserted  in  a  flat  surface  such  as  a  table  top,  are  com- 
bined and  ground  in  the  following  manner.  The  marbles  are 
first  cut  into  thin  sheets  from  one-eighth  to  one-fourth  of  an 
inch  thick,  which  are  cut  into  pieces  of  the  required  forms  and 
smoothed  on  the  edges  by  filing  and  rubbing.  Temporary  slips 
are  then  fixed  down  to  a  flat  surface,  within  which  the  pieces 
of  marble  to  form  the  pattern  are  arranged  in  their  proper 
situations,  face  downwards,  and  pressed  tightly  together,  plaster 
of  Paris  is  poured  over  the  whole,  and  a  slab  of  stone,  or  liner,  is 
laid  upon  the  plaster,  which  thus  cements  the  whole  into  one 
mass  exactly  the  same  as  the  single  row  of  squares  for  a  tesse- 
lated  pavement,  previously  explained.  When  the  plaster  is  set, 
the  surface  of  the  inlaid  work  is  ground  and  smoothed  as  a  runner 
upon  a  flat  slab,  until  it  presents  a  level  surface. 

The  work  is  now  laid  face  upwards  and  a  second  coat  of  plaster 
of  Paris,  and  a  second  liner  is  applied  to  the  face  of  the  work, 
which  is  thus  cemented  between  the  two  pieces  of  stone,  the  first 
of  which  is  then  removed.  To  effect  this  the  block  is  laid  with 
the  first  liner  upwards,  a  rim  of  clay  is  made  on  the  surface  of 
the  second  liner,  and  boiling  water  is  poured  in,  which  soon 
destroys  the  cohesion  of  the  first  coat  of  plaster,  which  is 
removed  together  with  the  liner,  thus  again  exposing  the  backs 
of  the  pieces  constituting  the  pattern,  which  are  then  cemented 
as  one  piece  in  the  recess,  previously  prepared  of  the  exact  size, 
in  the  slab  of  marble  in  which  the  pattern  is  to  be  inserted.  If 
the  work  is  not  intended  to  be  exposed  to  the  weather,  plaster 
of  Paris  is  used  as  the  cement,  but  if  the  work  is  required  to 
resist  moisture  or  frost,  the  slab  and  pattern  are  both  heated, 
and  cemented  together  with  the  soft  cement  used  for  marble  and 
stone  which  will  be  hereafter  described. 

The  cement  made  of  rosin  and  bees- wax  is  melted  in  a  pipkin, 

sculptured  works,  as  it  corrodes  the  surface  and  greatly  depreciates  the  artistic 
character  of  the  work. 

Granite  and  Porphyry  may  be  sawn  and  worked  after  the  same  general  manner 
as  marble,  but  from  the  greater  hardness  and  compactness  of  these  substances  the 
saw  cuts  more  rapidly  when  made  of  copper,  and  supplied  with  emery  and  water. 
The  grinding  is  best  effected  with  a  block  or  rubber  of  lead  also  supplied  with 
emery,  and  which  is  generally  used  like  a  rnuller  for  grinding  paint.  For  further 
particulars  on  working  granite  and  porphyry  the  reader  is  referred  to  Vol.  I,  pages 
169  to  172. 


APPLICATION    OF    MACHINERY  TO    WORKING    MARBLE.          1202 

poured  into  the  recess,  and  the  pattern  is  inserted  bodily,  so  soon 
as  the  cement  is  set,  the  second  liner  and  plaster  are  removed 
from  the  surface,  but  this  time  the  application  of  the  boiling 
water  is  not  necessary,  as  the  plaster  can  be  readily  detached 
from  the  smoothed  surface  with  a  chisel  applied  around  the 
edges.  The  entire  face  of  the  slab  is  now  ground  and  smoothed  to 
make  the  pattern  quite  level  with  the  margin,  after  which  any 
imperfections  that  may  exist  in  the  joinings  of  the  pieces,  are 
corrected  with  the  coloured  shell-lac  stopping  or  cement,  to  be 
hereafter  described,  and  the  work  is  finally  polished  as  usual. 

Marble  has  of  late  years  been  extensively  worked  by  machinery 
*iven  by  steam  power,  the  processes  are  closely  analogous  in 
principle  to  those  pursued  by  hand,  but  with  various  modifica- 
tions of  the  apparatus,  and  it  is  now  proposed  to  explain  briefly 
some  of  the  peculiarities  of  the  machine  processes. 

In  the  simplest  application  of  machinery  to  sawing  marble,  as 
for  making  one  or  two  cuts  in  a  large  block,  the  construction  of 
the  ordinary  stone  saw,  fig.  1086,  is  closely  followed,  but  the 
frame  is  made  much  stronger,  of  squared  timber- firmly  bolted 
together,  and  stayed  with  chains ;  to  constitute  three  sides  of  a 
rectangular  frame  ;  the  place  of  the  pole  and  tightening  chain  of 
the  saw5  fig.  1086,  is  occupied  by  two  fixed  beams,  and  the  saw 
is  held  and  stretched  by  means  of  two  clamps  with  screws  passing 
through  the  ends  of  the  frame,  and  tightened  by  nuts  on  the 
outside.  The  saw  frame  works  between  vertical  guide  posts  to 
keep  it  upright,  and  it  is  reciprocated  horizontally  by  a  con- 
necting rod  fixed  to  a  crank  driven  by  the  engine.  The 
connecting  rod  is  attached  to  the  frame  by  a  loop,  which  can  be 
placed  at  various  heights  so  as  always  to  keep  the  stroke  of  the 
connecting  rod  nearly  horizontal  notwithstanding  the  gradual 
descent  of  the  saw  in  the  cut. 

These  saw  frames  are  sometimes  made  as  large  as  16  feet 
long,  and  10  feet  high,  for  cutting  huge  blocks  of  marble ;  and  to 
prevent  the  great  weight  of  these  frames  from  pressing  on  the 
cut,  they  are  suspended  at  each  end  by  chains  or  slings  which 
vibrate  with  the  saw,  and  are  connected  with  a  counterpoise 
weight,  that  is  adjusted  to  allow  of  the  necessary  pressure  for 
the  cutting,  which  is  effected  with  sand  and  water  supplied  in 
the  same  manner  as  for  the  stone  saw  used  by  hand,  but  the  intro- 
duction of  the  guide  principle,  renders  the  chasing  of  the  stone  for 

VOL.    III.  N 


1203 


SAWING    MACHINE    FOR   CUTTING    MARBLE    SLABS. 


the  entry  of  the  saw  unnecessary.  In  some  cases  smaller  saws 
of  similar  construction  are  used  for  cutting  thick  slabs  into 
narrow  slips,  and  sometimes  several  cuts  are  made  at  once  by 
an  equal  number  of  saw  blades,  arranged  in  a  rectangular  frame, 
that  is  suspended  horizontally  by  vibrating  slings,  and  works 
between  vertical  guide  posts. 

In  the  horizontal  sawing  machine  for  marble  patented  by 
Mr.  James  Tulloch  in  1824,  the  entire  arrangements  are  com- 
bined in  a  very  effective  manner,  for  cutting  a  block  of  marble 
into  a  number  of  parallel  slabs,  of  any  thickness,  at  the  one 
operation.  The  iron  framework  of  the  machine,  shown  in  fig. 
1091,  consists  of  4  vertical  posts  strongly  connected  together  at 


FIG 


the  top  and  bottom,  to  form  a  stationary  frame  from  10  to  14 
feet  long,  4  to  5  feet  wideband  8  to  12  feet  high,  within  which 
the  block  of  marble  to  be  sawn  is  placed.  The  two  upright 


SAWING    MACHINE    FOR    CUTTING    MARBLE    SLABS.  1201 

posts  at  each  end  of  the  stationary  frame  have,  on  their  insides 
opposite  to  each  other,  perpendicular  grooves,  within  each  pair 
of  which  slides  up  and  down  a  square  vertical  frame ;  to  the 
lower  end  of  each  of  these  slides  is  affixed  a  spindle  carrying 
two  guide  pulleys,  or  riggers,  upon  which  the  horizontal  saw 
frame  rests,  and  is  reciprocated  backwards  and  forwards.  The  saw 
frame  is  thus  traversed  within  the  fixed  framing,  and  supported 
upon  the  four  guide  pulleys  of  the  vertical  slides,  which  latter 
are  themselves  suspended  by  chains  coiled  upon  two  small  drums 
placed  overhead.  On  the  same  spindle  with  the  drums  is  a  large 
wheel,  to  which  a  counterpoise  weight  is  suspended  by  a  chain. 
The  weight  of  the  counterpoise  is  so  adjusted  as  to  allow  the  saw 
frame  to  descend  when  left  to  itself,  and  which  thus  supplies 
the  necessary  pressure  for  causing  the  penetration  of  the  saws. 

The  saw  frame  is  made  rectangular,  and  from"  2  to  3  feet 
longer  than  the  distance  between  the  vertical  slides,  in  order  to 
permit  of  the  horizontal  traverse  of  the  saws,  which  is  from  18 
to  20  inches.  To  allow  of  the  blades  being  fixed  in  the  frame 
with  the  power  of  separate  adjustment,  every  blade  is  secured  by 
rivets  in  a  clamp  or  buckle  at  each  end ;  the  one  extremity  of 
the  buckle  embraces  the  saw,  the  other  is  made  as  a  hook,  the 
buckle  at  one  end  of  the  saw  is  hooked  upon  a  horizontal  bar 
fixed  across  the  end  of  the  saw  frame,  and  the  opposite  end  of 
the  frame  has  a  groove  extending  its  entire  width,  through  which 
a  separate  hook,  provided  with  a  vertical  tightening  wedge,  is 
inserted  for  every  saw,  which  thus  admits  of  being  replaced 
without  deranging  the  position  of  the  neighbouring  blades. 

The  distances  between  the  saws,  and  their  parallelism  with  the 
sides  of  the  frame,  are  adjusted  by  means  of  iron  blocks  made  of 
the  exact  thickness  required  in  the  slabs  of  marble,  the  blocks 
and  blades-  are  placed  alternately,  and  every  blade  is  separately 
strained  by  its  tightening  wedge  until  it  is  sufficiently  tense,  the 
blocks  are  sustained  between  two  transverse  bars,  called  gage 
bars,  and  are  allowed  to  remain  between  the  blades  to  give  them 
additional  firmness. 

The  traverse  of  the  saw  frame  is  given  by  a  jointed  connect- 
ing rod,  attached  by  an  adjustable  loop  to  a  long  vibrating  pen- 
dulum, that  is  put  in  motion  by  a  pair  of  connecting  rods,  placed 
one  over  the  other,  and  leading  from  two  cranks  driven  by  the 
engine.  All  three  connecting  rods  admit  of  vertical  adjustment 

N    2 


1205  SAWING    MACHINE    FOR   CUTTING  MARBLE    SLABS. 

on  the  pendulum.  The  connecting  rod  of  the  saw  frame  is 
placed  intermediately  between  the  other  two,  but  its  exact  posi- 
tion is  regulated  by  the  height  at  which  the  saws  are  working,  as 
it  is  suspended  by  a  chain  and  counterpoise  weight,  which  allow 
it  to  descend  gradually  downwards  on  the  pendulum,  with  the 
progress  of  the  cut,  so  as  always  to  keep  the  connecting  rod 
nearly  horizontal. 

In  the  London  Marble  Works  four  of  these  sawing  machines 
of  different  sizes  are  grouped  together,  with  the  driving  shaft 
and  pendulums  in  the  middle,  and  so  arranged  that  each  pair  of 
saw  frames  reciprocate  in  opposite  directions  at  the  same  time, 
in  order  to  balance  the  weight,  and  reduce  the  vibration. 

Another  mode  of  traversing  the  saw  frame  sometimes  adopted, 
is  by  means  of  a  vertical  frame  that  is  reciprocated  horizontally 
on  slides,  and  the  connecting  rod  instead  of  being  jointed,  is 
fixed  rigidly  to  the  saw  frame  and  slides  upon  a  vertical  rod. 
Various  other  unimportant  modifications  in  the  construction  of 
the  machines  are  also  adopted. 

One  of  the  most  difficult  points  in  the  application  of  these 
machines,  was  found  to  be  the  supplying  of  the  sand  and  water 
mechanically  to  the  whole  of  the  cuts  at  the  same  time.  This 
is  now  successfully  effected  by  the  following  arrangement.  Above 
the  block  of  marble  to  be  sawn,  is  fixed  a  water  cistern  or 
trough,  extending  across  the  whole  width  of  the  frame,  and 
measuring  about  one  foot  wide  and  one  foot  deep,  about  20 
small  cocks  are  arranged  along  each  side  of  the  cistern,  and  a 
small  but  constant  stream  from  each  of  the  cocks  is  received 
beneath  in  a  little  box,  a  sloping  channel  leads  from  every  box 
across  the  bottom  of  a  trough  filled  with  sand,  which  mingles 
with  the  water  and  flows  out  in  separate  streams  that  are  con- 
ducted to  each  of  the  saw  cuts.  In  the  first  construction  of  this 
apparatus  for  the  feed,  the  sloping  channels  were  led  straight 
across  the  bottom  of  the  sand  trough,  but  it  was  then  found 
that  the  water  excavated  little  tunnels  in  the  sand,  through 
which  it  flowed  without  carrying  the  sand  down.  This  difficulty 
was  overcome  by  leading  the  channels  across  the  bottom  of  the 
trough  in  a  curved  line,  when  viewed  in  plan.  The  form  of  the 
channels  is  shown  in  fig.  1092,  which  represents  four  channels 
cut  across  the  middle  of  their  length,  to  show  their  section, 
from  which  it  will  be  seen  that  the  channels  are  made  as  a 


SAWING    MACHINE    FOR    CUTTING    MARBLE    SLABS.  1206 

series  of  gothic  shaped  tunnels  supported  only  on  the  one  side, 
and  open  on  the  other  for  the  admission  of  the  sand  ;  the 
water  flows  through  these  tunnels,  FIG  log>2 

and  continually  washing  against  the 
convex  side  of  the  channel  under- 
mines the  sand,  which  falls  into  the 
water  and  is  carried  down ;  to  assist 
this  action  the  attendant  occasionally 
stirs  up  the  sand  to  loosen  it.  There 
is  a  sand  trough  and  set  of  channels 

on  each  side  of  the  water  cistern,  so  that  every  saw  cut  receives 
two  streams  of  sand  and  water  in  the  course  of  its  length. 

The  saws  having  been  adjusted  to  the  proper  distances  for  the 
required  slabs,  the  saw  frame  is  raised  by  means  of  a  windlass 
and  the  suspending  chains  attached  to  the  vertical  frames,  and 
the  block  of  marble  to  be  sawn  is  mounted  upon  a  low  carriage, 
and  drawn  into  its  position  beneath  the  saws,  and  adjusted  by 
wedges.  The  saws  are  then  lowered  until  they  rest  upon  the 
block,  the  counterpoise  weights  are  adjusted,  and  the  mixed 
sand  and  water  allowed  to  run  upon  the  saw  blades,  which  are 
put  in  motion  by  attaching  the  connecting  rod  to  the  pendulum. 
The  sawing  then  proceeds  mechanically  until  the  block  is 
divided  into  slabs,  the  weight  of  the  saw  frame  and  connecting 
rod  causing  them  gradually  to  descend  with  the  progress  of  the 
cutting. 

To  allow  the  sand  and  water  to  flow  readily  beneath  the  edges 
of  the  saw  blades,  it  is  desirable  that  the  horizontal  frame  should 
be  slightly  lifted  at  the  end  of  each  stroke.  This  is  effected  by 
making  the  lower  edges  of  the  frame,  which  bear  upon  the  guide 
pulleys,  straight  for  nearly  the  full  length  of  the  stroke,  but  with 
a  short  portion  at  each  end  made  as  an  inclined  plane,  which  on 
passing  over  the  guide  pulleys  lifts  the  frame  just  sufficiently  to 
allow  the  feed  to  flow  beneath  the  saws. 

For  cutting  slabs  of  marble  into  narrow  pieces,  such  as 
shelves,  and  which  is  effected  by  hand  with  grub  saws  as  explained 
at  page  1195,  a  machine  called  a  ripping  bed  is  employed,  in 
which  as  many  cuts  as  may  be  required  in  the  one  slab  are 
effected  simultaneously,  by  an  equal  number  of  circular  saws 
with  smooth  edges,  revolving  vertically,  and  fed  as  usual  with 
sand  and  water.  This  machine,  represented  in  fig.  1093,  consists 


1207 


MACHINE  FOR  NARROW  SLIPS  OF  MARBLE. 


of  a  bench  about  12  or  14  feet  long,  6  or  7  wide,  and  about 
2  feet  6  inches  high ;  upon  the  top  of  the  bench  is  fixed  two 
rails,  upon  which  a  platform  mounted  on  pulleys  is  drawn  slowly 
forward  by  a  weight.  The  horizontal  axis  carrying  the  saws 
revolves  about  nine  inches  above  the  platform,  and  to  ensure  the 
rotation  of  the  saws,  the  axis  is  provided  with  a  projecting  rib 
or  feather  extending  its  whole  length.  The  saws  are  made  as 
circular  plates,  about  17  inches  diameter  when  new.  The  saws, 
or  cutters,  are  clamped  between  two  collars  about  6  inches 
diameter,  fitted  so  as  to  slide  upon  the  spindle,  and  be  retained 
at  any  part  of  its  length  by  side  screws. 


Fia.  1093. 


The  saws  having  been  adjusted  to  the  required  distances  for 
the  widths  of  the  slips  to  be  cut,  and  fixed  by  the  side  screws, 
the  slab  of  marble  is  embedded  in  sand  upon  the  platform,  and 
the  edge  of  every  saw  is  surrounded  on  one  side  with  a  small 
heap  of  moist  sand.  The  saws  are  then  set  in  motion  so  as  to 
cut  upwards,  and  the  platform  is  slowly  traversed  under  the 
saws  by  the  weight,  which  keeps  the  slab  of  marble  constantly 
pressing  against  the  edges  of  the  revolving  saws,  until  the  slab  is 
entirely  divided  into  slips. 

When  the  saws  are  new,  they  nearly  reach  the  upper  surface 
of  the  platform,  and  a  moderate  thickness  of  sand,  just  sufficient 
to  form  a  bed  for  the  slab  of  marble,  raises  it  high  enough  to 


SAWING    CIRCULAR   WORKS    IN    MARBLE.  1208 

allow  the  saws  to  pass  entirely  through  the  thickness  of  the  slab; 
but  as  the  saws  are  reduced  in  diameter  by  wear,  it  becomes 
necessary  to  employ  a  thicker  layer  of  sand,  or  to  use  a  supple- 
mentary platform  to  raise  the  slab  to  the  proper  height.  To 
avoid  this  inconvenience,  an  improvement  has  been  recently 
introduced  by  mounting  the  axis  of  the  saws  in  a  vertical  slide, 
which  is  adjusted  by  a  rack  and  pinion,  so  as  to  allow  the  edges 
of  the  saw  to  penetrate  exactly  to  the  required  depth. 

Circular  pieces  of  marble,  such  as  the  tops  of  round  tables, 
and  other  objects,  from  about  6  feet  diameter  to  the  small  circular 
dots  sometimes  used  in  tesselated  pavements,  are  sawn  to  the 
circular  form  by  means  of  revolving  cylindrical  cutters,  con- 
structed on  much  the  same  principle  as  the  crown  saws  for  wood 
described  on  page  802,  Vol.  II.  The  slab  to  be  sawn  is  placed 
horizontally  on  a  bench,  and  the  axis  of  the  machine  works  ver- 
tically above  it  in  cylindrical  bearings,  which  allow  the  spindle  to 
slide  through  them,  so  as  to  be  elevated  or  depressed  according 
to  circumstances.  The  spindle  is  suspended  at  the  upper  end  by 
a  swing  collar  attached  to  a  connecting  rod,  that  is  jointed  to  the 
middle  of  a  horizontal  lever.  The  weight  of  the  vertical  rod 
and  cutter  supplies  the  pressure  for  the  cutting,  and  the  whole 
is  raised  for  the  admission  of  the  work  by  a  rope  attached  to 
the  end  of  the  lever,  and  passed  over  a  pulley  as  shown  in 
fig.  1094. 

For  circles  of  small  diameter,  the  cutters  are  made  as  hollow 
cylinders  of  sheet  iron  of  various  diameters,  and  each  attached 
by  screws  to  a  circular  disk  of  cast  iron,  as  shown  in  section  in 
fig.  1096.  The  cutter  is  screwed  on  the  lower , end  of  the  spindle, 
just  the  same  as  a  chuck  on  a  lathe  mandrel,  except  that  the 
spindle  is  placed  vertical  instead  of  horizontal.  To  ensure  free 
access  for  the  sand  and  water  beneath  the  cutter,  one  or  two 
notches,  about  three-quarters  of  an  inch  wide,  are  generally 
made  in  the  lower  edge. 

For  large  circles,  the  apparatus  is  made  stronger  than  that 
shown  in  fig.  1094,  and  the  vertical  spindle  is  fitted  at  its  lower 
extremity  with  a  circular  plate,  to  which  is  bolted  a  wooden 
cross,  phown  in  plan  in  fig.  1097?  and  in  elevation  in  fig.  1098, 
the  cross  has  radial  grooves  about  18  inches  long  near  the 
outer  extremities  of  the  four  arms.  The  cutters  consist  of 
detached  plates  of  iron  from  6  to  18  inches  long,  of  various 


1207 


SAWING    MACHINE    FOR    NARROW    SLIPS    OF    MARBLE. 


of  a  bench  about  12  or  14  feet  long,  6  or  7  wide,  and  about 
2  feet  6  inches  high ;  upon  the  top  of  the  bench  is  fixed  two 
rails,  upon  which  a  platform  mounted  on  pulleys  is  drawn  slowly 
forward  by  a  weight.  The  horizontal  axis  carrying  the  saws 
revolves  about  nine  inches  above  the  platform,  and  to  ensure  the 
rotation  of  the  saws,  the  axis  is  provided  with  a  projecting  rib 
or  feather  extending  its  whole  length.  The  saws  are  made  as 
circular  plates,  about  17  inches  diameter  when  new.  The  saws, 
or  cutters,  are  clamped  between  two  collars  about  6  inches 
diameter,  fitted  so  as  to  slide  upon  the  spindle,  and  be  retained 
at  any  part  of  its  length  by  side  screws. 


FIG.  1093. 


The  saws  having  been  adjusted  to  the  required  distances  for 
the  widths  of  the  slips  to  be  cut,  and  fixed  by  the  side  screws, 
the  slab  of  marble  is  embedded  in  sand  upon  the  platform,  and 
the  edge  of  every  saw  is  surrounded  on  one  side  with  a  small 
heap  of  moist  sand.  The  saws  are  then  set  in  motion  so  as 
cut  upwards,  and  the  platform  is  slowly  traversed  under  th< 
saws  by  the  weight,  which  keeps  the  slab  of  marble  constantly 
pressing  against  the  edges  of  the  revolving  saws,  until  the  slab  is 
entirely  divided  into  slips. 

When  the  saws  are  new,  they  nearly  reach  the  upper  surfac 
of  the  platform,  and  a  moderate  thickness  of  sand,  just  sufficient 
to  form  a  bed  for  the  slab  of  marble,  raises  it  high  enough  to 


SAWING    CIRCULAR   WORKS    IN    MARBLE.  1208 

allow  the  saws  to  pass  entirely  through  the  thickness  of  the  slab; 
but  as  the  saws  are  reduced  in  diameter  by  wear,  it  becomes 
necessary  to  employ  a  thicker  layer  of  sand,  or  to  use  a  supple- 
mentary platform  to  raise  the  slab  to  the  proper  height.  To 
avoid  this  inconvenience,  an  improvement  has  been  recently 
introduced  by  mounting  the  axis  of  the  saws  in  a  vertical  slide, 
which  is  adjusted  by  a  rack  and  pinion,  so  as  to  allow  the  edges 
of  the  saw  to  penetrate  exactly  to  the  required  depth. 

Circular  pieces  of  marble,  such  as  the  tops  of  round  tables, 
and  other  objects,  from  about  6  feet  diameter  to  the  small  circular 
dots  sometimes  used  in  tesselated  pavements,  are  sawn  to  the 
circular  form  by  means  of  revolving  cylindrical  cutters,  con- 
structed on  much  the  same  principle  as  the  crown  saws  for  wood 
described  on  page  802,  Vol.  II.  The  slab  to  be  sawn  is  placed 
horizontally  on  a  bench,  and  the  axis  of  the  machine  works  ver- 
tically above  it  in  cylindrical  bearings,  which  allow  the  spindle  to 
slide  through  them,  so  as  to  be  elevated  or  depressed  according 
to  circumstances.  The  spindle  is  suspended  at  the  upper  end  by 
a  swing  collar  attached  to  a  connecting  rod,  that  is  jointed  to  the 
middle  of  a  horizontal  lever.  The  weight  of  the  vertical  rod 
and  cutter  supplies  the  pressure  for  the  cutting,  and  the  whole 
is  raised  for  the  admission  of  the  work  by  a  rope  attached  to 
the  end  of  the  lever,  and  passed  over  a  pulley  as  shown  in 
fig.  1094. 

For  circles  of  small  diameter,  the  cutters  are  made  as  hollow 
cylinders  of  sheet  iron  of  various  diameters,  and  each  attached 
by  screws  to  a  circular  disk  of  cast  iron,  as  shown  in  section  in 
fig.  1096.  The  cutter  is  screwed  on  the  lower  ,end  of  the  spindle, 
just  the  same  as  a  chuck  on  a  lathe  mandrel,  except  that  the 
spindle  is  placed  vertical  instead  of  horizontal.  To  ensure  free 
access  for  the  sand  and  water  beneath  the  cutter,  one  or  two 
notches,  about  three-quarters  of  an  inch  wide,  are  generally 
made  in  the  lower  edge. 

For  large  circles,  the  apparatus  is  made  stronger  than  that 
shown  in  fig.  1094,  and  the  vertical  spindle  is  fitted  at  its  lower 
extremity  with  a  circular  plate,  to  which  is  bolted  a  wooden 
cross,  shown  in  plan  in  fig.  1097,  and  in  elevation  in  fig.  1098, 
the  cross  has  radial  grooves  about  18  inches  long  near  the 
outer  extremities  of  the  four  arms.  The  cutters  consist  of 
detached  plates  of  iron  from  6  to  18  inches  long,  of  various 


1209 


SAWING    CIRCULAR    WORKS    IN    MARBLE. 


widths,  according  to  the  thickness  of  .the  work.  The"  cutters 
are  curved  as  segments  of  a  cylinder,  of  the  particular  diameter 
they  are  required  to  cut,  and  are  each  rivetted  to  a  clamp  that 


FIGS.  1094. 


n 


passes  through  the  radial  groove,  and  is  retained  by  a  wedge.  The 
number  and  length  of  the  cutters  is  solely  a  matter  of  conveni- 
ence, as  a  single  cutter,  when  put  in  rotation,  would  make  a 
circular  groove,  and  several  cutters  are  only  employed  in  order 
to  expedite  the  process.  But  every  different  diameter  requires  a 
different  curve  in  the  cutters,  and  which  must  all  be  placed  at 
exactly  the  proper  distance  from  the  center  of  rotation. 

The  horizontal  bench  upon  which  the  marble  is  laid,  is  generally 
a  temporary  structure,  adjusted  to  suit  the  thickness  of  the 
object  to  be  sawn.  Works  of  large  diameter  are  seldom  more 
than  one  or  two  inches  thick,  but  those  of  small  diameter  are 
frequently  much  thicker,  and  sometimes  three  or  four  thin 
pieces  are  cemented  upon  each  other,  and  cut  at  one  operation. 
Short  pillars  are  sometimes  sawn  out  of  an  irregular  block  in  a 
similar  manner,  instead  of  being  chipped  and  turned.  And  it 
has  been  proposed  that  long  cylinders,  and  tubes  of  stone,  should 


REVOLVING    LAPS    FOR   GRINDING    MARBLE.  1210 

be  cut   with  cylinders   of  sheet  iron   of  corresponding  length, 
put  in  rotation,  and  supplied  with  sand  and  water. 

Marble  works  of  small  and  medium  size,  are  ground  flat  upon 
horizontal  revolving  laps,  after  the  same  general  method  as  that 
pursued  by  the  lapidary,  but  with  a  proportionate  increase  of 
size  in  the  lap,  which  is  supplied  as  usual  with  sand  and  water. 
The  laps  for  marble  works  are  made  as  circular  plates  of  cast 
iron,  from  6  to  14  feet  diameter,  and  about  3  inches  thick  when 
new ;  they  are  mounted  in  various  ways  upon  vertical  spindles, 
so  that  their  upper  sides  or  faces  may  be  about  2  feet  6  inches 
above  the  ground.  Across  the  face  of  the  lap,  or  as  it  is  called 
the  sanding  plate,  one  or  two  strong  square  bars  of  wood,  faced 
with  iron,  are  fixed  so  that  their  lower  sides  may  just  avoid 
touching  the  face  of  the  lap,  and  their  edges  present  perpendi- 
cular faces,  from  5  to  6  inches  high,  at  right  angles  to  the  face  of 
the  lap.  The  wooden  bars  serve  as  stops  to  prevent  the  work 
from  being  carried  round  by  the  lap,  and  also  as  guides  to  ensure 
the  work  being  ground  square. 

The  piece  of  marble  is  laid  flat  upon  the  lap,  with  the  face  to 
be  ground  downwards,  and  the  side  of  the  work  in  contact  with 
the  guide  bar.  Water  is  allowed  to  drip  upon  the  plate  from  a 
cistern  fixed  above,  and  small  quantities  of  sand  are  thrown  on 
as  required.  During  the  progress  of  the  work  the  workman 
leans  upon  the  marble,  the  position  of  which  is  shifted  occasion- 
ally to  expose  both  the  work  and  the  lap  to  an  equal  amount  of 
wear,  and  prevent  the  formation  of  ridges,  but  which  is  less 
likely  to  occur  with  iron  laps  used  for  grinding  large  surfaces  of 
marble,  than  when  small  objects  are  applied  upon  lead  laps,  as  by 
the  lapidary  and  mechanician. 

The  one  side  of  the  marble  having  been  reduced  to  a  flat 
surface,  the  work  is  turned  over  to  grind  the  adjoining  face,  and 
the  first  face  is  held  in  contact  with  the  perpendicular  side  of 
the  guide  bar,  in  order  to  present  the  second  face  of  the  work  to 
the  lap  exactly  at  right  angles  to  the  first.  When  two  pieces  of 
similar  size  are  to  be  ground  each  on  the  one  face  and  two  edges, 
as  for  the  upright  sides  of  a  chimney-piece,  the  two  pieces  of 
marble  are  cemented  together  back  to  back  with  plaster  of  Paris, 
(a  process  that  is  called  lining),  and  the  pair  are  ground  as  one 
piece  on  all  four  faces  ;  in  this  case  the  flat  sides  are  first  ground 
parallel  to  each  other,  or  of  equal  thickness  on  the  two  edge/?, 


1211  GRINDING    MACHINE    FOR    LARGE    SLABS    OF    MARBLE. 

,and  the  latter  are  then  ground  square  by  placing  the  sides  in 
contact  with  the  guide  bar. 

When  the  lap  is  of  moderate  size,  one  guide  bar  only  is 
employed,  and  it  is  fixed  across  the  diameter  of  the  plate,  which 
then  allows  of  two  workmen  being  employed  on  the  opposite 
sides ;  but  large  grinding  plates  sometimes  have  two  or  three 
bars  placed  at  equal  distances  across  the  face,  and  four  or  six 
workmen  may  then  be  employed  at  the  same  time  upon  separate 
pieces  of  marble. 

The  sand  and  water  are  continually  thrown  from  the  lap  by 
the  centrifugal  force,  and  the  large  sizes  of  the  works  sometimes 
applied,  prevents  the  use  of  a  rim  standing  up  above  the  level  of 
the  lap  to  catch  the  wet,  as  used  by  lapidaries.  Every  workman, 
therefore,  stands  within  a  kind  of  trough  like  a  box,  about  three 
feet  high,  without  a  top  or  back  ;  the  troughs  serve  as  a  protec- 
tion to  the  workmen,  who  would  otherwise  be  exposed  to  a 
continued  shower  of  sand  and  water. 

The  surfaces  of  large  slabs  are  in  some  cases  ground  upon 
revolving  plates  ;  in  this  case  the  axis  is  placed  entirely  beneath 
the  surface  of  the  plate,  somewhat  as  in  fig.  1039,  and  the  slab  is 
traversed  by  two  men  over  the  face  of  the  plate  to  grind  it 
equally,  but  the  machine  next  described  is  better  adapted  for 
large  slabs  of  marble  requiring  tolerable  accuracy. 

Large  slabs  of  marble  and  stone  are  ground  very  accurately  in 
a  machine  patented  by  Mr.  Tulloch,  and  called  a  grinding  bed. 
In  this  machine,  represented  in  fig.  1099,  the  slab  to  be  ground 
is  placed  horizontally  upon  a  moving  bed,  and  the  grinding  is 
effected  by  sand  and  water,  by  means  of  a  large  flat  plate  of  iron 
resting  upon  the  surface  of  the  slab.  The  two  surfaces  are 
traversed  over  each  other  with  a  compound  motion,  partly  eccen- 
tric and  partly  rectilinear,  so  as  continually  to  change  their 
relative  positions.  The  machine  consists  of  a  frame  about  9  feet 
long,  6  feet  wide,  and  8  feet  high ;  about  2  feet  from  the  ground 
is  mounted  a  platform,  that  is  very  slowly  reciprocated  horizon- 
tally for  a  distance  of  from  1  to  2  feet,  according  to  the  size 
of  the  slab,  by  means  of  a  rack  and  pinion  placed  beneath,  and 
worked  alternately  in  both  directions. 

Above  the  platform  are  fixed  vertically  two  revolving  shafts, 
having  at  their  upper  extremities  horizontal  toothed  wheels  of 
equal  diameter  which  are  driven  by  means  of  a  central  toothed 


.GRINDING    MACHINE    FOR    LARGE    SLABS    OF    MARBLE.          1212 

wheel  keyed  on  the   driving  shaft.     The  two  vertical  shafts  are 
thus  made  to  revolve  at  equal  velocity  or  turn  for  turn,  and  to 


FIG.  1099. 


?, 

disi 


heir  lower  ends  are  attached  two  equal  cranks  placed  parallel  to 
each  other,  the  extremities  of  which  therefore  describe  equal 

ircles  in  the  same  direction.  To  these  cranks  the  iron  grinding 
plate  or  runner  is  connected  by  pivots  fitting  two  sockets  placed 
upon  the  central  line  of  the  plate.  The  cranks  are  made  with 
ial  grooves  so  that  the  pivots  can  be  fixed  by  wedges  at  any 

istance  from  the  center  of  the  cranks.  When  the  machine  is 
put  in  motion  the  grinding  plate  is  thus  swung  round  bodily  in 
a  horizontal  circle  of  the  same  diameter  as  the  throw  of  the 
cranks,  which  is  usually  about  1 2  inches,  and  consequently  every 
portion  of  the  surface  of  the  grinding  plate  would  describe  a 
circle  upon  the  surface  of  the  slab  being  ground  if  the  latter  were 
stationary.  But  by  the  slow  rectilinear  movement  of  the  plat- 
form the  slab  is  continually  shifted  beneath  the  plate  so  as  to 


1213          GRINDING    MACHINE    FOR    LARGE    SLABS    OF    MARBLE. 

place  the  circles,  or  rather  the  cycloids,  in  a  different  position, 
and  it  is  only  after  many  revolutions  of  the  cranks  that  the  same 
points  of  the  surfaces  of  the  grinding  plate  and  slab  are  a  second 
time  brought  in  contact. 

The  grinding  plate  is  raised  for  the  admission  of  the  slab  by 
means  of  four  chains  suspended  from  a  double  lever,  and  attached 
to  the  arms  of  a  cross  secured  to  the  center  of  the  upper  surface 
of  the  plate,  which  is  thus  lifted  almost  like  a  scale  pan.  For 
slabs  that  are  much  thicker  or  thinner  than  usuLal,  the  principal 
adjustment  is  obtained  by  the  removal  or  addition  of  separate 
beds,  or  loose  boards,  laid  upon  the  platform  to  support  the  slab 
at  the  proper  height.  Slabs  that  are  too  large  to  be  ground 
over  the  whole  surface  at  the  one  operation,  are  shifted  once  or 
twice  during  the  grinding,  to  expose  the  surface  equally  to  the 
action  of  the  grinding  plate. 

The  necessary  pressure  for  grinding,  is  given  by  the  weight  of 
the  horizontal  plate,  which  is  supported  almost  entirely  by  the 
work,  as  the  pivots  of  the  cranks  merely  enter  the  sockets,  and 
allow  the  plate  to  descend  when  left  to  itself.  For  delicate 
works  a  counterpoise  weight  is  attached  to  the  double  lever  so  as 
to  regulate  the  pressure  on  the  work. 

The  sand  and  water  are  applied  to  the  grinding  surfaces  in 
much  the  same  manner  as  in  the  iron  runners  used  by  hand 
previously  described.  The  grinding  plate  is  made  on  the  upper 
side  with  a  raised  rim  like  a  tray,  and  the  bottom  of  the  tray  is 
perforated  with  numerous  holes  about  1J  inch  diameter  arranged 
at  equal  distances  apart.  The  sand  and  water  are  thrown  into 
the  tray  at  intervals  in  small  quantities,  and  run  through  the 
holes  and  between  the  surfaces  of  the  slab  and  grinding  plate, 
which  are  thus  uniformly  supplied  with  the  feed  that  ultimately 
makes  its  escape  around  the  edges  of  the  grinding  plate. 

Various  qualities  of  sand  may  be  employed  according  to  the 
perfection  of  surface  required,  and  very  flat  surfaces  are  pro- 
duced by  this  machine.  The  grounding  or  smoothing  of  the 
best  works  is  effected  with  a  succession  of  fine  emeries,  with 
which  the  surfaces  may  be  made  very  smooth,  and  almost 
polished ;  but  from  motives  of  economy,  the  grounding  of 
ordinary  works  is  more  frequently  completed  by  hand,  with 
grit  stones  and  snake  stone  before  the  work  is  finally  polished 
on  another  machine}  described  on  page  1216. 


MOULDING   MACHINE    FOR    WORKS    IN   MARBLE. 


1214 


Rectilinear  mouldings  in  marble  are  wrought  by  machinery  in 
a  manner  altogether  different  from  the  hand  process  of  working 
mouldings,  in  which,  as  previously  described,  nearly  the  whole  of 
the  material  is  removed  with  chipping  chisels,  and  the  surfaces 
>f  the  mouldings  are  only  smoothed  by  abrasion.    In  the  machine 
>rocess,  on  the  contrary,  the  whole  of  the  material  is  removed 
fith  revolving  grinders,  by  which  the  work  is  reduced  to  the 
jquired  form,  and  left  smooth  at  the  one  operation. 
The  machine  for  working  rectilinear  moulding,  or  as  it  is  called 
moulding  bed,  closely  resembles  in  its  construction  the  ripping 
jd  described  at  page  1207,  except  that  the  frame  carrying  the 
evolving  grinders  is  provided  with  the  power  of  vertical  adjust- 
icnt  by  a  screw  placed  beneath,  in  order  to  raise  the  grinder  to 
the  proper  height  to  suit  the  thickness  of  the  marble,  and  that 
instead  of  the  grinders,  being  thin  circular  sheets  of  iron,  they 
msist  of  solid  cylinders  of  cast  iron  turned  to  the  counterpart 
>rms  of  the  required  mouldings.     Indeed  the  ordinary  ripping 
>ed  is  occasionally  used  for  working  mouldings  on  large  works, 
id  when  it  is  provided  with  the  vertical  adjustment  for  elevating 
depressing  the  axis  to  any  required  position,  the  ripping  bed 
equally  suitable  for  working  mouldings  ;  but  as  the  latter  are 
in  general  only  required  on  slips  of  marble  only  a  few  inches 
ride,  a  narrow  machine  is  usually  employed  for  the  purpose. 

The  forms  of  some  of  the  grinders  are  shown  in  figs.  1100  to 
.102  ;  the  outline  represents  the  grinder,  and  the  shaded  part 


FIGS.  1100. 


1101. 


1102. 


1> 


meath,  the  entire  compound  moulding  that  would  be  produced 
)y  the  same.  A  separate  grinder  is  required  for  every  different 

loulding,  and  consequently  a  large  number  of  grinders  have  to 
>e  provided  to  meet  the  demand  for  variety.  They  are  all 
)ierced  with  a  central  hole  fitted  to  the  axis  of  the  machine  into 

rhich  they  are  to  be  employed,  and  secured  either  by  a  wedge 


1215  MOULDING    MACHINES    FOR  WORKS    IN    MARBLE. 


or  a  side  screw,  so  that  they  admit  of  being  readily  exchanged 
when  a  different  form  of  moulding  is  required. 

The  grinder  of  suitable  form  having  been  selected  it  is  fixed 
on  the  axis  of  the  machine,  the  slip  of  marble  is  cemented  with 
plaster  of  Paris  upon  the  bed,  and  the  frame  carrying  the  spindle 
is  adjusted  by  the  screws  beneath  to  the  proper  position,  to 
allow  the  grinders  to  penetrate  the  marble  to  the  required  depth 
for  the  production  of  the  moulding.  As  in  the  ripping  bed,  the 
grinder  is  made  to  revolve  so  as  to  cut  upwards  towards  the 
surface,  and  the  attendant  keeps  a  small  heap  of  moist  sand 
constantly  in  contact  with  the  face  of  the  grinder.  The  weight 
attached  to  the  sliding  bed  by  a  line  passing  over  a  pulley  keeps 
the  work  constantly  advancing  in  a  straight  line  towards  the 
grinder  as  fast  as  it  is  cut,  and  the  work  finally  presents  a  com- 
pound rectilinear  moulding  of  exactly  the  counterpart  form  of 
the  grinder.  Mouldings  on  the  edges  of  narrow  slips  are  some- 
times wrought  in  pairs,  as  in  fig.  1102,  the  two  pieces  being 
cemented  together  sideways  as  one  block,  and  which  is  placed 
edgeways  upon  the  machine. 

Circular  mouldings  in  marble,  such  as  the  base  of  a  column,  a 
vase,  or  similar  object,  are  generally  wrought  by  turning  in  a 
lathe  after  the  manner  described  in  Vol.  I.  page  167.  Small 
flat  circular  mouldings,  such  as  are  sometimes  seen  in  the  corners 
of  chimney  pieces,  are  ground  to  their  forms  by  machinery  in 
much  the  same  general  manner  as  the  rectilinear  mouldings,  but 
the  machine  described  on  page  1209,  for  cutting  out  small  circles 
of  marble,  is  employed  for  grinding  the  small  circular  patterns. 

The  grinders  are  made  of  cast-iron  turned  to  the  counterpart 
form  of  the  pattern,  as  shown  in  section  in  fig.  1095,  and 
screwed  upon  the  upright  spindle  of  the  machine  the  same  as  the 
circular  cutters.  The  counterpart  grinders  are  kept  supplied 
with  moist  sand,  and  the  grinding  is  continued  until  the  circular 
pattern  is  entirely  developed,  the  works  are  afterwards  polished 
in  the  lathe,  as  described  at  page  1077. 

The  polishing  of  rectilinear  works  in  marble,  by  machinery, 
closely  resembles  the  polishing  of  flat  slabs  by  hand,  previously 
described,  the  chief  differences  being,  that  for  large  slabs,  from 
2  to  6  rubbers  or  blocks  are  employed,  and  that  they  are  reci- 
procated by  the  machine  instead  of  by  hand.  The  slab  of 
marble  to  be  polished,  is  laid  upon  a  flat  bench  or  table  about 


POLISHING   MACHINE    FOR    MARBLE. 


1216 


12  feet  long  and  6  feet  wide.  At  a  moderate  height  above  the 
bench  is  fixed  a  crank  driven  by  the  engine,  a  connecting 
rod  from  which  leads  to  an  iron  swing  frame,  working  as  a  pen- 
dulum placed  2  or  3  feet  from  the  end.  Fig.  1103  represents 


the  side  view  of  the  polishing  bed ;  the  swing  frame  consists 
simply  of  two  rods  moving  upon  centers  above,  and  carrying  near 
their  lower  extremities  a  horizontal  bar  extending  the  entire 
width  of  the  bench ;  to  this  bar  as  many  separate  iron  rods  are 
attached  as  there  are  rubbers  to  be  employed  at  one  time,  and 
jvery  rod  is  jointed  to  its  own  rubber,  which  for  flat  surfaces 
msists  of  a  block  of  wood  about  2  feet  long  and  6  inches  wide, 
>vered  with  thick  felt,  as  explained  at  page  1089,  articles  3 
id  4.  The  attachments  of  the  connecting  rods  to  the  crank 
id  pendulum  are  all  capable  of  adjustment,  so  that  the  length 
)f  stroke  can  be  readily  changed  to  suit  the  size  of  the  work  in 
>urse  of  being  polished,  but  generally  the  stroke  is  about 
feet  long. 

The  rubbers  are  used  with  the  succession  of  powders  explained 
on  pages  1076  and  1077,  and  the  weight  of  the  blocks  and  rods 
supply  the  pressure.  Several  narrow  rubbers  are  used  instead  of 
one  wide  rubber,  in  order  to  allow  each  rubber  to  adapt  itself 
readily  to  any  trifling  irregularities  in  the  surface  of  the  slab. 
The  rubbers  are  shifted  across  the  width  of  the  slab,  by  sliding 


1217  MANUFACTURE    OF   PLATE    GLASS. 

them  to  another  position  on  the  horizontal  bar  of  the  pendulum 
frame,  and  the  platform  of  the  machine  is  traversed  endways  by 
a  chain  and  drum,  or  a  rack  and  pinion,  to  expose  the  work 
equally  to  the  action  of  the  rubbers. 

Rectilinear  mouldings  are  polished  in  the  same  manner,  except 
that  elastic  rubbers  are  employed.  These  are  made  of  coarse 
cloth,  like  sacking  ;  generally  old  sugar  bags  are  used  for  the 
purpose ;  they  are  cut  into  strips  about  six  inches  wide,  folded 
lengthways,  and  nailed  through  the  middle  of  the  fold  close 
together  to  a  block  of  wood,  so  as  to  present  when  complete  a 
surface  8  or  9  inches  wide,  composed  of  the  edges  of  the  cloth, 
the  loose  filaments  of  which  penetrate  into  the  angles  of  the 
mouldings.  For  polishing  the  edges  of  narrow  works  in  marble 
several  pieces  are  fixed  close  together  edgeways  in  a  wooden 
trough,  and  they  are  all  polished  at  the  same  time. 


The  grinding  and  polishing  of  plate  glass  by  machinery,  is 
perhaps  the  largest  example  of  the  production  of  plane  surfaces 
by  grinding,  and  a  brief  outline  of  the  mode  of  proceeding  will 
be  here  offered. 

In  the  manufacture  of  plate  glass,  the  materials  are  first  fused 
in  melting  pots  made  of  Stourbridge  clay,  which  measure  from 
30  to  40  inches  diameter,  and  3  to  4  feet  high.  The  pots  are  made 
in  the  form  of  a  truncated  cone,  being  rather  smaller  at  the 
bottom  than  the  top,  and  are  capable  of  containing  a  sufficient 
quantity  of  the  melted  glass  to  form  four  or  five  plates  of  the 
largest  size.  After  the  materials  have  been  thoroughly  fused 
together,  a  sufficient  quantity  of  the  melted  glass  to  form  a 
single  plate,  is  removed  by  iron  ladles  from  the  large  melting 
pot  to  smaller  pots  called  cuvettes,  which  have  been  previously 
heated  in  another  furnace.  The  glass  now  in  a  pasty  condition 
is  placed  in  the  pots  while  they  are  in  the  furnace,  which  is 
then  closed  up,  and  kept  at  a  considerable  heat  for  some  hours, 
until  all  the  air  bubbles  have  been  expelled  and  the  glass  is 
sufficiently  fluid  to  be  poured. 

The  pot  is  then  removed  from  the  furnace,  and  carried  on  a 
truck  to  an  iron  table  or  bench,  having  a  flat  surface  about  18 
feet  long  and  10  feet  wide,  two  bars  of  iron  of  equal  thickness  to 
the  desired  plate  are  laid  upon  the  face  of  the  table  near  the 


MANUFACTURE    OP    PLATE-GLASS.  1218 

edges.  The  fluid  glass  is  poured  on  the  table  and  spread  with 
iron  or  copper  tools  ;  an  iron  roller  about  15  inches  diameter, 
equal  in  length  to  the  width  of  the  table,  and  weighing  about 
30  cwt.  is  rested  upon  the  two  iron  bars  and  traversed  over  the 
face  of  the  glass,  to  roll  it  out  like  dough  to  a  uniform  thickness. 
To  insure  the  rotation  of  the  roller  in  a  straight  line  along  the 
plate,  it  is  provided  at  each  end  with  toothed  wheels  that  work 
in  corresponding  racks  fixed  on  the  sides  of  the  iron  table,  and 
the  roller  is  drawn  along  the  table  by  means  of  two  chains,  coiled 
around  the  ends  of  the  cylinder  and  worked  by  a  windlass. 

When  the  glass  has  been  rolled  flat,  the  cylinder  is  received  at 
the  end  of  the  table  upon  two  arms  counterpoised  by  means  of 
levers  placed  beneath,  so  as  to  allow  of  the  heavy  roller  being 
raised  or  lowered  by  two  or  three  men.  The  plate  still  red  hot 
and  yielding,  is  slid  from  the  table  upon  the  flat  surface  of  a 
carriage  which  is  wheeled  to  the  annealing  oven,  upon  the  bed  of 
which  the  plate  is  pushed  and  allowed  to  remain  for  several  hours 
to  cool  gradually. 

The  plates  when  cold  are  examined  as  to  their  condition,  and 
such  plates  as  present  defects  in  the  glass,  or  irregularities  in  the 
surface  that  it  would  be  tedious  to  grind  out,  are  cut  with  the 
diamond  into  smaller  pieces,  but  the  nearly  perfect  plates  are 
kept  as  near  their  full  size  as  possible,  and  merely  squared  on  the 
edges. 

The  plates  of  glass  now  measure  about  half-an-inch  thick,  and 
the  surface  is  full  of  small  irregularities,  presenting  a  mottled 
appearance,  the  roughest  side  being  generally  that  which  was 
placed  downwards  upon  the  bed  of  the  annealing  oven,  and  copied 
all  the  irregularities  of  the  bricks  of  which  the  bed  of  the  oven  is 
formed.  The  side  of  the  glass  that  was  uppermost  in  the  oven,  is 
comparatively  smooth  and  bright  from  the  action  of  the  fire, 
although  in  many  cases  this  surface  is  not  so  nearly  flat  as  the 
lower.  The  plates  have  therefore  to  be  ground  flat  and  polished 
on  both  sides,  formerly  this  was  effected  entirely  by  hand,  but  of 
late  years  the  rough  grinding  with  coarse  sand,  and  the  polishing 
with  crocus,  are  almost  always  done  by  machinery,  and  hand 
labour  is  only  resorted  to  for  the  intermediate  process  of 
smoothing  with  fine  emery. 

The  grinding  and  polishing  machines  employed  for  plate  glass 
differ  somewhat  in  construction  in  various  manufactories,  but  a 

VOL.  III.  O 


1219  GRINDING    MACHINES    FOR    PLATE    GLASS. 


single  example  of  each  will  sufficiently  explain  the  general 
method. 

The  grinding  machines  employed  for  the  largest  plate  glass 
are  arranged  in  pairs  along  the  grinding  room  ;  every  pair  of 
machines  is  driven  by  one  central  beam,  and  consists  of  two 
benches  of  stone  15  feet  long,  8  feet  wide,  and  18  inches  high, 
placed  about  10  feet  asunder ;  upon  each  of  these  benches  one 
or  more  plates  of  glass  are  embedded  in  plaster  of  Paris,  close 
together,  and  quite  level.  Other  plates  of  glass  are  cemented 
upon  the  lower  faces  of  two  swing  tables  or  runners,  which  are 
traversed  over  the  fixed  beds,  by  a  horizontal  frame  or  beam 
about  SO  feet  long  ;  the  machinery  for  driving  the  beam  is  fixed 
in  a  frame  about  6  feet  square  and  18  inches  high,  placed 
between  the  two  grinding  benches.  A  horizontal  shaft  fixed 
underground,  extends  throughout  the  length  of  the  grinding 
room  between  the  lines  of  benches,  and  the  motion  from  the 
shaft  is  communicated  to  every  pair  of  machines,  by  a  pair  of 
bevil  wheels  leading  to  a  central  crank  that  revolves  horizontally, 
and  has  a  radius  of  about  2  feet ;  the  arm  of  the  crank  is  attached 
by  a  pivot  to  the  center  of  the  horizontal  beam.  Four  other 
cranks  of  the  same  radius  are  placed  parallel  to  the  central 
driving  crank,  one  at  each  corner  of  the  square  frame,  and  serve 
to  guide  the  traverse  of  the  horizontal  beam,  which  is  thus 
swung  in  a  circle  of  four  feet  diameter  in  a  manner  somewhat 

O 

similar  to  the  grinding  bed  for  marble,  fig.  1099.  The  beam  is 
supported  at  various  parts  of  its  length  by  chains  suspended 
from  the  roof  of  the  building,  which  allow  of  the  traverse  of  the 
beam,  and  serve  for  raising  it  by  means  of  levers  for  the  removal 
of  the  work. 

Near  each  end  of  the  beam  is  attached,  with  the  power  of 
adjustment  for  position,  a  small  sliding  frame  carrying  bearings 
for  the  reception  of  the  central  pivot  of  the  swing  table  or 
runner,  which  consists  of  a  strong  frame  of  wood  covered  with 
boards,  and  measuring  8  feet  long  and  6  feet  wide,  placed  face 
downwards  upon  the  bench ;  a  central  pivot  stands  up  from  the 
back  of  the  runner,  and  enters  the  bearing  fixed  on  the  horizontal 
beam,  which  thus  communicates  a  circular  swinging  motion  to 
the  center  of  the  runner,  exactly  the  same  as  that  of  the  driving 
crank ;  and  the  runner  being  free  to  revolve  upon  its  pivot, 
acquires  a  continual  rotation  around  its  own  axis.  By  the  com- 


GRINDING    MACHINES    FOR    PLATE    GLASS.  1220 

bination  of  the  two  movements  the  relative  position  of  the  fixed 
bench  and  runner  are  continually  changing ;  this  tends  to  the 
mutual  correction  of  the  two  surfaces  of  the  glass,  and  greatly 
assists  the  equal  distribution  of  the  sand  and  water  used  in 
grinding.  The  horizontal  beam  makes  about  fifty  circulating 
strokes  in  a  minute,  and  the  runners  revolve  upon  their  own'axes 
about  once  to  every  five  or  six  strokes.  The  position  of  the 
runners  upon  the  driving  beam  is  shifted  once  or  twice  during 
the  grinding,  to  distribute  the  action  as  uniformly  as  possible 
over  the  entire  surfaces  of  the  glass  plates. 

The  largest  plates  of  glass  are  nearly  equal  in  size  to  the  fixed 
bench,  and  these  are  imbedded  singly  upon  the  bench  with  the 
most  irregular  side  upwards ;  but  more  generally  plates  of 
medium  and  small  size  are  ground  together  ;  they  are  selected 
of  uniform  thickness,  and  arranged  close  together  upon  the 
bench,  with  the  largest  plates  in  the  middle  and  the  smallest  at 
the  ends.  The  runner  is  covered  by  one  or  two  plates  at  most, 
as  small  pieces  would  be  liable  to  be  thrown  off  by  the  centrifugal 
force. 

All  the  irregularities  of  the  surfaces  are  first  ground  out  with 
sharp  river  sand,  that  has  been  washed  and  sifted  into  two  sizes  ; 
the  sand  and  water  are  thrown  on  by  hand  occasionally,  and 
when  the  plates  have  been  ground  quite  flat,  the  finer  sand  is 
employed,  and  followed  by  emery  of  two  finer  sizes,  applied  as 
usual  in  succession,  in  order  to  remove  the  scratches  made  by 
the  coarser  powders.  The  plates  of  glass  are  thoroughly  washed 
between  every  change  of  grinding  powder,  and  when  the  one  side 
of  the  glass  has  been  ground  with  the  finer  sizes  in  succession, 
the  plates  are  inverted,  and  the  same  routine  is  followed  on  the 
second  side. 

The  grinding  machines  do  not  however  admit  of  being  em- 
ployed with  very  fine  emery,  as  the  close  approximation  of  large 
surfaces  travelling  over  each  other  at  a  considerable  velocity, 
causes  so  much  friction  that  it  would  be  liable  to  tear  the  surface 
of  the  glass,  and,  consequently,  as  the  plates  become  sufficiently 
smooth  to  require  the  application  of  fine  emeries,  the  velocity 
and  pressure  should  be  proportionally  reduced,  and  a  greater 
degree  of  care  and  management  is  required ;  it  is  therefore  found 
to  be  preferable  to  effect  the  smoothing  of  plate  glass  by  hand. 

The  plates  are  smoothed  upon  stone  benches  of  suitable  size, 

o2 


1221  SMOOTHING    PLATE    GLASS    BY    HAND. 

about  2  feet  high,  made  very  flat  upon  their  surfaces,  and 
covered  with  wet  canvas.  One  large  plate  nearly  equal  to  the 
size  of  the  bench,  and  two  or  three  plates  of  about  half  the  size, 
are  usually  given  out  as  a  set  of  work.  The  large  plate  is  laid 
upon  the  wet  canvas  which  serves  to  hold  it  firmly,  emery  and 
water  are  spread  over  the  surface,  and  one  of  the  small  plates  is 
used  as  a  grinder  or  runner.  If  the  plates  be  large,  a  few  flat 
lead  weights  of  about  14  Ibs.  each  are  laid  near  the  middle  of 
the  runner,  to  distribute  the  pressure  uniformly,  and  the  runner 
is  traversed  over  the  lower  plate  with  a  swinging  stroke  back- 
wards and  forwards,  so  as  to  describe  nearly  a  semicircle  around 
the  center  of  the  runner,  which  is  at  the  same  time  shifted  a 
few  inches  during  the  stroke.  Every  stroke  follows  a  slightly 
different  path  from  the  preceding  one,  and  the  runner  is  also 
gradually  twisted  round  as  the  smoothing  proceeds.  The  com- 
bination of  these  movements,  serves  to  expose  every  part  of  the 
surfaces  of  the  bed  plate  and  runner  to  an  equal  amount  of 
grinding,  and  also  to  distribute  the  emery  very  uniformly. 

Small  plates  are  smoothed  by  young  girls,  and  large  plates 
which  require  greater  dexterity  and  a  proportionate  increase  in 
the  amount  of  traverse,  are  smoothed  by  two  women ;  who  stand 
on  opposite  sides  of  the  bench,  and  placing  their  outstretched 
hands  flat  upon  the  runner  swing  it  with  a  stroke  of  five  or  six 
feet.  The  employment  appears  most  masculine,  but  it  is  found 
that  the  smoothing  is  upon  the  whole  executed  better  by  women 
than  men,  as  only  a  moderate  force  is  required,  and  from  the 
greater  delicacy  of  touch  possessed  by  females,  they  more  readily 
appreciate  when  any  particles  of  grit  have  become  accidentally 
mixed  with  the  emery. 

About  six  sizes  of  carefully  washed  emery  are  used  in  the 
smoothing,  and  between  every  size,  the  plates,  canvas,  bench  and 
hands  are  thoroughly  washed,  perfect  cleanliness  in  the  clothing 
is  also  quite  essential,  as  a  particle  of  coarse  grit  would  make  a 
scratch  that  would  require  the  smoothing  of  the  plates  to  be 
recommenced.  The  fine  emery  last  employed  gives  a  very 
smooth  and  partly  polished  surface,  which  is  completed  with  the 
machine  next  described. 

The  polishing  machine  has  a  bed  15  feet  long  and  8  feet  wide, 
that  is  mounted  upon  rollers,  and  slowly  traversed  sideways,  a 
space  of  4  feet  to  and  fro,  by  means  of  a  rack  and  pinion  beneath. 


POLISHING    MACHINES    FOR    PLATE-GLASS.  1222 

A  few  inches  above  the  bed  are  reciprocated  longitudinally,  2 
beams  or  carriages,  each  about  18  feet  long  and  9  inches  wide, 
and  consisting  of  two  cast  iron  side  plates  connected  together  at 
intervals,  and  supported  at  each  end  upon  two  small  wheels, 
that  run  upon  a  short  railway  at  the  end  of  the  traversing  table. 
The  carriages  are  placed  4  feet  asunder,  and  reciprocated  about 
2  feet  by  means  of  two  cranks  fixed  opposite  to  each  other  on 
the  same  axis,  so  that  the  beams  work  in  opposite  directions, 
the  one  advancing  as  the  other  recedes. 

The  plates  of  glass  are  embedded  close  together,  with  their 
surfaces  quite  level,  upon  moveable  platforms  that  are  afterwards 
fixed  upon  the  traversing  bed,  and  the  polishing  is  effected  with 
a  series  of  rubbers,  placed  1  foot  asunder  and  measuring  8  by  6 
inches,  covered  with  thick  felt,  and  attached  to  the  reciprocating 
carriages,  which  drag  the  rubbers  backwards  and  forwards  over 
the  surface  of  the  glass,  while  the  latter  is  traversed  beneath  the 
rubbers,  a  space  equal  to  the  distance  between  the  two  lines  of 
rubbers,  to  expose  all  parts  of  the  glass  equally  to  their  action. 

Every  rubber  is  separately  attached  to  one  of  the  two  carriages, 
to  allow  it  to  ply  uniformly  to  the  surface  of  the  glass,  this  is 
effected  as  follows,  between  the  two  side  plates  of  the  beam  are 
fixed,  near  the  top  and  bottom  edges,  two  cross  pieces  having 
square  holes,  through  which  slides  vertically  a  square  bar,  the 
lower  end  of  which  projects  about  2  inches  below  the  beam,  and 
is  rounded  semi-cylindrically.  The  rubber  is  made  quite  detached, 
with  a  central  cavity  at  the  back  to  fit  the  end  of  the  upright 
bar,  which  thus  forms  a  joint  that  allows  the  rubber  to  adjust 
itself  to  any  trifling  irregularities  of  the  surface  over  which  it  is 
traversed,  and  the  rubbers  admit  of  being  readily  removed  while 
the  plates  of  glass  are  being  exchanged.  The  pressure  is  given 
separately  upon  every  rubber  by  two  lead  weights  of  about  1 5  Ibs. 
each  fixed  one  on  each  side  of  the  upright  bar. 

The  powder  generally  employed  for  polishing  plate  glass  by 
machinery  is  the  Venetian  pink  of  the  colour-man,  a  cheap 
powder  which  contains  only  a  small  proportion  of  the  oxide  of 
iron,  mixed  with  earthy  matter  that  renders  the  powder  less 
active,  and  allows  of  the  free  use  of  water,  which  serves  to 
reduce  the  friction  and  prevent  the  glass  becoming  heated  by 
the  action  of  the  rubbers.  Tripoli,  crocus,  or  putty  powder 
used  with  water,  are  too  active  to  produce  a  high  polish  on  glass, 


1223  MANUFACTURE    OF    SHEET    GLASS. 


and  therefore  they  are  generally  employed  dry  for  the  last  finish 
of  glass  polished  by  hand.  But  the  great  amount  of  rubbing 
surface,  the  velocity  and  power  employed  for  polishing  plate 
glass  by  machinery,  renders  the  use  of  dry  powders  inadmissible, 
as  the  surface  would  be  torn  by  the  friction,  and  the  heat  evolved 
would  be  liable  to  break  the  glass. 

Sometimes  old  plate  glass,  that  has  become  scratched,  is  re- 
polished  ;  when  the  plates  are  large,  and  sufficiently  numerous, 
they  are  repolished  by  machinery,  just  the  same  as  new  glass, 
but  more  generally  old  plates  are  repolished  by  hand,  as  the 
process  can  be  then  restricted  principally  to  the  scratched  por- 
tions of  the  surface. 

The  polishing  is  commenced  with  tripoly  on  cloth  rubbers  of 
the  usual  form,  and  finished  with  putty  powder  or  crocus.  The 
pressure  is  generally  given  as  in  hand  calendering,  by  attaching 
the  rubber  to  the  lower  end  of  an  upright  pole,  suspended  from 
a  long  horizontal  spring  fixed  overhead,  like  that  of  a  pole  lathe. 
The  elasticity  of  the  spring  supplies  the  pressure,  and  the  work- 
man has  only  to  push  the  rubber  backwards  and  forwards,  but 
the  process  is  both  laborious  and  tedious  with  large  plates,  and 
from  the  irregular  action  of  the  hand,  the  surfaces  of  glass  thus 
polished  present  a  wavy  appearance  much  inferior  to  those 
polished  by  machinery. 


Sheet  glass  or  flattened  glass,  is  manufactured  by  blowing  the 
glass  first  into  the  form  of  a  spherical  bulb,  which  is  afterwards 
elongated,  by  alternate  heating,  blowing  and  swinging,  into  a 
cylinder  about  3  feet  long  and  8  inches  diameter,  with  rounded 
ends,  which  as  the  last  process  of  blowing  are  opened  out,  and 
the  ends  are  cut  smooth  with  a  diamond  traversed  in  an  upright 
frame  around  the  cylinder,  which  is  then  cut  through  on  the  one 
side  longitudinally,  with  a  diamond  inserted  near  the  extremity 
of  a  light  rod,  and  drawn  through  the  inside  of  the  cylinder 
under  the  guidance  of  a  straight  edge.  The  cylinder  is  then 
placed  with  the  cut  upwards  in  a  reverberatory  furnace,  and  the 
heat  causes  the  cylinder  gradually  to  open  as  a  sheet,  which  is 
gently  flattened  down  on  the  bed  of  the  furnace,  with  tools  like 
blunt  garden  rakes  made  of  iron  or  wood. 

To  improve  the  flatness,  several  sheets  are  afterwards  laic 


GRINDING    MACHINES    FOR   SHEET    GLASS. 


1224 


upon  each  other  in  a  second  reverberatory  furnace  with  a  leve 
bed,  the  heat  of  the  furnace  and  the  weight  of  the  superincum- 
bent mass,  causes  the  lower  sheets  of  glass  to  become  sufficiently 
flat  for  ordinary  use,  notwithstanding  that  there  are  many  little 
irregularities  in  its  surface,  arising  from  the  imperfect  action  of 
the  flattening  process.  For  the  best  purposes  these  irregu- 
larities are  removed  by  grinding  and  polishing,  and  a  brief, 
notice  of  the  method  pursued  in  an  extensive  manufactory  will 
be  here  subjoined. 

The  grinding  room  contains  about  140  grinding  machines, 
arranged  in  double  rows  of  10  each,  and  the  annexed  diagram 


FIG.  1104. 


I.-- 


fig.  1104,  may  be  considered  to  represent  roughly  the  moving 
parts  of  every  machine,  the  framing  being  represented  by  the 
dotted  lines. 


1225  GRINDING    MACHINES    FOR    SHEET    GLASS. 

The  framework  consists  of  continuous  beams  1,  1,  united  by 
vertical  posts  2,  2,  bounding  every  machine,  the  whole  firmly 
united.  Above  the  framing  extends  an  axis  3,  3,  carrying  for 
every  machine  one  pair  of  bevil  wheels  which  turn  the  upright 
shaft  4,  and  its  crank  5,  to  the  right  or  left  at  pleasure.  The 
pin  of  the  crank  5  communicates  a  circular  motion  to  that  point 
of  the  moving  table  to  which  it  is  attached,  while  the  fixed 
radius  bar  6,  7,  8  restrains  the  center  of  the  table  to  describe  an 
arc  about  the  point  6,  the  two  motions  conjointly  bring  all  parts 
of  the  running  surface  successively  in  opposition  to  nearly  every 
part  of  the  lower  bed,  which  latter  lies  on  railway  bars  9,  9,  and 
is  very  slowly  reciprocated  to" and  fro  by  the  bar  10,  which  runs 
through  the  building,  and  is  traversed  about  two  feet  by  a  crank, 
that  is  made  slowly  to  revolve  by  a  worm  wheel  and  tangent 
screw,  one  screw  serving  for  two  cranks  united  to  two  lines  of 
the  machines.  The  whole  arrangement  is  most  massive  and 
imposing. 

The  circle  described  by  the  crank  5,  is  about  two- thirds  of 
the  length  of  the  moving  table,  the  lower  face  of  which  is  covered 
with  slate  upon  which  the  glass  is  cemented,  another  sheet  of 
glass  is  cemented  upon  the  lower  table,  and  the  upper  table  is 
loaded  with  4  or  8  weights  placed  in  the  respective  panels  of 
the  frame.  When  from  swinging  the  upper  table  about  by 
hand,  it  is  judged  that  one  of  the  corners  bears  too  hard,  the 
weights  are  removed  from  this  corner.  Coarse  emery  and  water 
are  used  for  the  grinding,  and  when  the  machines  are  used  with 
finer  emeries  for  smoothing,  the  whole  apparatus  is  carefully 
washed,  for  the  convenience  of  which  there  are  numerous  racks 
and  tanks  between  the  rows  of  machines.  In  some  manufac- 
tories the  plates  of  glass  are  smoothed  by  rubbing  them  one  upon 
the  other  by  hand. 

After  the  sheet  glass  has  been  ground  flat  and  smoothed,  it 
is  polished  in  another  room  by  the  machinery  rudely  shown 
in  figs.  1105  to  1107.  1,  1,  is  a  long  main  shaft  extending 
throughout  the  length  of  the  building,  and  having  for  every  row 
of  the  machines  one  double  and  two  single  cranks,  which  move 
the  two  long  central  beams,  2,  2,  to  the  right,  and  the  two 
exterior  beams,  2',  2',  to  the  left  at  the  same  instant,  by  the 
intervention  of  connecting  rods,  as  usual. 

The  travelling  beams  or  rods  carry  rubbers,  3,  3,  3,  3,  about 


POLISHING    MACHINES    FOR   SHEET    GLASS. 


1226 


12  by  5  inches  on  the  face,  and  covered  with  leather ;  they 
are  suspended  by  a  joint  to  the  loaded  levers,  4,  4',  which  press 
them  on  the  glass.  To  raise  them  up  and  retain  them,  the 
piece  5  is  laid  down  in  the  position  5',  which  holds  up  the  lever 


1105. 


as  at  4',  as  the  joint  which  unites  4  and  5  is  situated  in  the 
mortise  through  the  long  travelling  beam  2,  at  the  part  repre- 
sented by  the  dot  in  the  figure  to  the  left ;  so  that  when  the 
rubber  is  at  work  the  weight  5  cannot  be  misplaced,  and  when 
is  laid  down  as  at  5',  no  shaking  will  allow  the  rubber  to 
lescend  accidentally.     The  rubbers  all  assume  an  inclined  posi- 
tion, from  the  several  tables  carrying  the  glass  having  a  very 
slow  transverse  motion,  simultaneously  throughout  the  entire  line 
)f  machines,  which  is  effected  somewhat  after  the  manner  of  the 
mexed  figure,  1108. 

The  main  shaft  1,1,  communicates  with  a  pair  of  sliding  bevil 
wheels  6,  6  ;  these  through  7  move  the  tangent  screw  8,  and 
thence  the  worm  wheel  9,  which  latter,  by  the  pair  of  bevil 
/heels  10,  11,  moves  the  long  shaft  carrying  the  line  of  pinions 
2, 12,  one  or  two  of  which  are  under  every  table,  and  traverse 
the  same   by  aid  of  plain  rollers  13,  13.     A  tumbling  bob  is 
affixed  to  the  table  nearest  the  cranks  and  gear,  by  which  the 
position  of  the  pair  of  bevils  6,  6,  are  shifted  to  make  the  tables 
traverse  first  in  the  one  and  then  in  the  opposite  direction. 


1227       GRINDING-TOOLS    FOR    PLANE    SURFACES    IN    GLASS,    ETC. 


The  polishing  machines  make  about  50  or  60  strokes  in  the 
minute,  and  the  grinding  machines  about  20  to  SO  strokes  in 


FIG.  1108. 


1] 


12 


the  minute,  and  every  machine  is  so  arranged  as  to  admit  of 
being  readily  detached  from  the  others  without  impeding  the 
movement  of  the  principal  parts. 


It  has  been  explained  in  the  second  volume,  at  pages  870 
to  872,  that  the  production  of  accurate  plane  surfaces  by 
grinding  is  a  process  of  great  uncertainty,  and  that  the  plane 
surfaces  of  metal  required  in  mechanical  construction,  are  more 
easily  and  correctly  produced  by  the  methods  of  filing  and 
scraping,  described  at  pages  876,  878 ;  but  these  methods  are 
inapplicable  to  substances,  such  as  glass  or  speculum  metal,  that 
do  not  admit  of  the  application  of  cutting  tools,  and  conse- 
quently when  these  hard  materials  have  to  be  wrought  into 
plane  surfaces,  it  is  essential  to  produce  the  necessary  degree  of 
accuracy  by  grinding  alone.  The  grinding  tool  employed  for 
the  purpose  is  generally  a  flat  surface  of  brass,  supplied  with 
abrasive  powder  moistened  with  water  or  oil.  The  surface  is  in 
most  cases  larger  than  the  object  to  be  ground,  which  is  rubbed 
by  hand  upon  the  grinding  tool  with  straight,  circular,  or  ellip- 
tical strokes,  applied  in  all  directions  ;  but  these  grinding  tools, 
although  they  may  be  originally  produced  by  the  method  of 
scraping,  soon  lose  the  required  accuracy,  and  from  the  particles 
of  the  polishing  powder  becoming  embedded  in  the  surfaces, 
their  restoration  by  the  method  of  scraping  is  impracticable. 

The  plane  surfaces  of  the  grinding  tools  themselves,  have 
therefore  to  be  produced  as  nearly  accurate  as  possible  by 


GRINDING-TOOLS    FOR    PLANE    SURFACES    IN    GLASS,    ETC.        1228 

grinding,  and  the  method  explained  on  page  871  is  pursued  with 
all  possible  care.  Three  surfaces,  generally  of  brass,  are  operated 
upon  at  the  same  time,  and  serve  for  mutual  correction  by  being 
rubbed  one  upon  the  other,  in  the  succession  explained  at  pages 
877  and  878,  with  reference  to  testing  the  condition  of  planome- 
ters  produced  by  scraping. 

The  two  surfaces  found  to  have  the  same  error  are  rubbed 
together,  first  with  large  circular  strokes,  in  order  that  the 
operator  may  feel  at  what  parts  of  their  surfaces  they  bear  the 
hardest,  or  appear  to  hang  together ;  these  parts  are  then  placed 
in  contact  and  rubbed  with  short  strokes,  either  straight  or  cir- 
cular, applied  longitudinally  or  transversely,  according  as  they 
may  feel  to  offer  the  greater  resistance  to  the  one  or  other 
motion,  the  surfaces  being  rubbed  together  in  the  direction,  and 
just  for  the  distance,  that  they  appear  to  move  stiffly  upon  each 
other. 

Great  care  is  required  to  avoid  the  introduction  of  new  errors, 
exactly  as  in  scraping  planometers,  and  the  surfaces  must  be 
frequently  wiped  clean  and  tried  upon  each  other,  first  to  feel 
that  they  bear  uniformly  when  tried  at  the  four  diagonals,  and 
when  these  larger  errors  are  removed,  the  surfaces  are  rubbed 
together  with  short  strokes,  in  order  that  they  may  mutually 
brighten  the  highest  points  of  their  respective  surfaces.  The 
grinding  is  continued  under  these  tests  until  all  three  surfaces 
feel  to  slide  smoothly  and  equably  over  each  other  in  all  direc- 
tions, the  final  test  being  that  :.when  the  whole  of  the  grinding 
powder  is  removed,  and  they  are  rubbed  upon  each  other,  the 
surfaces  should  be  uniformly  covered  with  small  bright  spots 
close  together,  so  as  to  give  the  surfaces  a  finely  mottled  or 
bronzed  appearance.  The  degree  of  accuracy  required  to  present 
this  uniformly  brightened  surface,  is  however  exceedingly  diffi- 
cult to  attain  by  the  process  of  grinding. 

In  the  case  of  plane  surfaces  in  glass  required  for  optical 
purposes,  as  in  the  parallel  disks  employed  in  sextants,  great 
accuracy  is  required,  and  in  the  ordinary  method  of  grinding 
and  polishing,  much  difficulty  is  experienced  from  the  absence  of 
control  over  the  distribution  of  the  grinding  powder  upon  the 
surfaces  under  formation.  To  obviate  this  inconvenience,  Mr. 
Andrew  Ross,  of  London,  was  induced  to  investigate  the  causes 
which  led  to  the  inaccuracy  of  the  grinding  process,  and  he  has 


1229          GRINDING    PLANE    SURFACES    FOR    OPTICAL    PURPOSES. 

succeeded  in  pointing  out  the  principal  source  of  error,  and  also 
the  method  by  which  it  may  be  avoided. 

Upon  a  careful  examination  of  the  process  of  grinding  two 
surfaces  upon  each  other,  whether  plane  or  curved,  Mr.  A.  Ross 
found  that  the  principal  errors  occurred  in  the  direction  in  which 
the  two  surfaces  were  rubbed  upon  each  other,  and  which  arises 
from  the  unequal  distribution  of  the  grinding  powder.  In  the 
act  of  traversing  the  object  over  the  metal  surface  the  grinding 
powder  is  pushed  away  by  the  advancing  edge  of  the  object, 
while  near  its  middle  an  excessive  quantity  of  the  powder  is 
accumulated,  and  consequently  the  object  is  ground  concave  near 
the  middle,  and  in  the  return  stroke  it  picks  up,  at  the  extreme 
edges,  a  small  quantity  of  the  new  grinding  powder  that  has  not 
been  crushed  in  working,  and  therefore  acts  with  more  energy, 
and  rounds  off  the  extreme  edge.  The  combination  of  the  two 
errors,  makes  the  object  that  should  be  a  plane  surface,  of  the 
irregular  section  shown  in  the  exaggerated  diagram,  fig.  1109. 

For  optical  purposes,  the  rounding  off  at  the  edges  is  not  very 
important,  as  the  difficulty  may  be  overcome,  either  by  grinding 
the  glass  of  a  larger  size  than  is  ultimately  required,  and  after- 
wards reducing  the  diameter  so  as  to  remove  the  rounded  edges, 
or  the  edges  may  be  covered  by  a  ring  of  pasteboard  or  metal, 
so  as  to  prevent  that  portion  from  interfering  with  the  action  of 
the  instrument.  It  is  therefore  the  concavity  in  the  middle,  that 
is  the  principal  difficulty  in  optical  glasses. 

FIGS.  1109.  1110. 


0 


J     000 


0 


Mr.  A.  Ross  discovered  that  the  accumulation  of  the  grinding 
powder  near  the  middle  of  the  glass,  arose  from  the  capillary 
attraction  of  the  moistened  powder,  and  that  by  the  employment 
of  the  grinding  powder  in  a  dry  state,  the  source  of  the  most 
important  error  was  removed.  The  grinding  powder  when  used 
dry  cuts  less  rapidly  than  when  moistened,  but  from  the  greater 


GRINDING    PARALLEL    DISKS    FOR    SEXTANTS.  1230 

exactness  of  the  method,  a  much  smaller  amount  of  abrasion 
suffices  to  produce  the  plane  surface,  and  consequently  the  dry 
process  is  but  little  more  tedious  than  the  wet. 

In  grinding  and  polishing  the  parallel  disks  of  glass  for  sex- 
tants, the  one  surface  is  first  ground  flat,  sometimes  singly,  but 
more  generally  from  motives  of  economy  five  are  ground  at  the 
same  time.  The  disks  are  arranged  in  the  order  shown  in  the 
diagram,  fig.  1110.  The  surface  of  the  one  tool  having  been 
wiped  quite  clean  and  dry,  every  disk  is  slightly  moistened  by 
breathing  upon  it.  The  disk  is  then  placed  upon  the  lower  tool 
with  moderate  pressure ;  and  if  the  disks  be  tolerably  flat,  the 
capillary  attraction  will  suffice  for  retaining  them  in  position 
during  the  grinding.  A  small  quantity  of  finely  washed  emery 
is  then  dusted  upon  every  disk,  the  second  tool  is  placed  over 
the  whole,  and  attached  to  a  line  leading  to  a  pulley  placed 
overhead,  and  from  which  a  counterpoise  weight  is  suspended  to 
regulate  the  pressure  upon  the  disks,  which  should  be  only 
moderate.  The  upper  tool  is  then  rubbed  with  elliptical  strokes 
continually  varied  in  direction,  and  the  tools  are  occasionally 
changed  end  for  end,  in  order  to  place  the  surfaces  in  all  possible 
relations  to  each  other. 

The  surface  upon  which  the  glass  disks  are  attached  is  always 
the  lower  tool ;  and  the  emery  that  is  pushed  off  the  disks  falls 
on  the  lower  surface,  and  is  not  picked  up  by  the  upper  tool  in 
the  return  stroke,  which  as  previously  mentioned,  would  be  liable 
to  round  the  extreme  edges.  By  this  arrangement  it  is  only 
the  tolerably  uniform  layer  of  emery  that  remains  attached  to 
the  upper  grinding  tool  that  is  employed,  and  the  principal 
dependance  for  flatness  is  placed  upon  the  condition  of  this  tool. 
Water  is  used  with  the  emery  by  most  opticians,  but  by  Mr. 
Ross  the  emery  is  used  dry  ;  and,  to  examine  the  progress  of  the 
work,  the  upper  tool  is  removed,  and  the  grinding  powder  blown 
away  with  a  pair  of  bellows,  as  wiping  with  a  cloth  would  leave 
particles  of  the  powder  attached  to  the  face  of  the  disks. 

When  the  disks  have  been  ground  flat  over  their  whole  sur- 
faces on  one  side,  they  are  removed  from  the  lower  tool,  which 
is  thoroughly  cleaned ;  the  disks  are  then  arranged  as  before, 
with  their  second  faces  upwards,  and  ground  flat.  But  it  will 
now  happen  that  the  two  sides,  although  they  may  be  plane  sur- 
faces, are  not  parallel  to  each  other,  and  therefore  the  positions 


1231  GRINDING    PLANE    SURFACES    FOR   SPECULA. 

of  the  disks  upon  the  lower  tool  are  interchanged,  1  being  placed 
in  the  position  of  5,  and  2  in  that  of  4,  and  the  central  disk  is 
twisted  round  in  the  opposite  direction.  The  whole  are  then 
ground  in  the  same  manner  as  before,  until  flat  in  their  second 
positions,  when  the  disks  are  again  interchanged  ;  and  the  pro- 
cess is  repeated  until  both  sides  of  the  disks  are  made  quite 
parallel  to  each  other,  and  they  collectively  present  a  level 
surface  in  whatever  order  they  may  be  arranged  upon  the  lower 
tool.  The  disks  are  lastly  polished  either  with  oxide  of  iron,  or 
putty  powder. 

Plane  mirrors,  made  of  speculum  metal,  and  employed  in 
reflecting  telescopes,  are  ground  to  a  plane  surface  upon  flat 
grinding  tools  prepared  as  above  described.  The  grinding  tool 
is  much  larger  than  the  specula  to  be  ground,  and  is  supplied 
with  a  small  quantity  of  fine  washed  emery.  The  specula  are 
rubbed  singly  upon  the  tool,  with  the  fingers  like  a  muller,  until 
they  are  ground  perfectly  flat.  The  principal  difficulty  is,  how- 
ever, experienced  in  producing  the  high  polish  required  in 
reflecting  surfaces  without  impairing  the  accuracy  of  the  plane 
surface  obtained  in  grinding.  The  polisher  is  generally  of  cast 
iron,  grooved  over  its  entire  surface,  so  as  to  divide  it  into 
squares,  and  covered  with  pitch,  or  a  resinous  cement,  exactly 
in  the  same  manner  as  in  the  polishers  used  for  concave  specula, 
the  methods  of  working  which  will  be  briefly  described  in  the 
fourth  section  of  this  chapter.  Great  importance  is  attached  to 
the  sizes  of  the  polishers  relatively  to  those  of  the  specula,  as  if 
the  polishers  are  made  too  large,  the  edges  of  the  specula  will  be 
rounded  off,  or  made  convex  j  and  if  the  polishers  are  made  too 
small,  the  specula  will  be  wrought  concave. 

Small  plane  specula  are  usually  polished  several  at  the  same 
time.  They  are  arranged  close  together  to  make  up  a  circle, 
and  with  their  faces  quite  level.  The  polisher  is  also  circular; 
and  Mr.  A.  Ross  considers  that  the  specula  are  the  most  accu- 
rately polished  when  the  diameter  of  the  polisher  is  about  one- 
thirtieth  greater  than  that  of  the  circle  of  specula. 

Elliptical  specula,  measuring  above  3  inches  by  2,  are  com- 
monly polished  singly,  and  Mr.  Gambadella  found  that  he  suc- 
ceeded the  best  when  he  employed  a  round  polisher  of  the  same 
size  as  the  inner  diameter  of  the  oval.  The  Earl  of  Rosse  found 
that  he  was  enabled  to  polish  specula  of  this  size  very  perfectly 


'" 


THE    PRODUCTION   OP  CYLINDRICAL    SURFACES    BY   ABRASION.        1232 

with  a  polisher  of  three  inches  diameter  applied  in  his  machine 
for  grinding  and  polishing  concave  specula  briefly  described  in 

e  fourth  section  of  this  chapter. 

Speaking  of  polishing  plane  mirrors,  the  Earl  of  Rosse  says  : — 
"  When  the  metal  is  polished,  it  is  tested  in  the  usual  way  by 
viewing  an  object  alternately  by  direct  and  reflected  vision,  with 
a  very  good  thirty  inch  achromatic,  the  aperture  of  which  has 
been  previously  contracted  to  an  inch  and  three  quarters. 
If  the  metal  is  concave,  it  is  worked  with  shorter  strokes  for 
about  half  an  hour,  and  then  tried  ;  it  will  be  found  to  have 
become  less  concave,  possibly  convex  ;  in  the  latter  case  it  is  to 
be  worked  with  longer  strokes  ;  thus,  with  the  utmost  facility, 
a  metal  can  be  worked  alternately  concave  and  convex;  and, 
with  a  little  practice,  the  limit  between  the  two  can  be  hit  with 
such  exactness,  that,  even  with  the  severe  test  of  a  thirty  inch 
achromatic,  no  deviation  from  the  plane  can  be  perceived,  and 
the  loss  of  light  will  be  the  only  evidence  that  the  rays  have 
suffered  reflexion  before  their  incidence  on  the  object  glass." 
(Trans.  Royal  Society,  1840,  p.  524.) 

SECT.  II. — THE  PRODUCTION  OF  CYLINDRICAL  SURFACES  BY  ABRASION. 

CYLINDRICAL  works  in  metal,  of  small  diameter,  and  considerable 
length,  such  as  slender  rods,  are  difficult  to  be  turned  of  strictly 
uniform  diameter,  because  from  their  weakness  they  are  liable  to 
spring  away  from  the  turning  tool.  This  liability  is,  to  a  con- 
siderable extent,  counteracted  by  the  application  of  supports 
called  back  stays,  or  sliding  guides,  which  will  be  adverted  to  in 
the  succeeding  volume ;  but,  nevertheless,  after  slender  rods 
have  been  turned  as  nearly  uniform  in  diameter  as  possible,  they 
still  retain  numerous  irregularities,  which,  although  not  observ- 
able to  the  eye,  may  be  readily  detected  by  passing  the  rod 
between  the  fingers. 

Shorter  or  thicker  cylindrical  rods,  that  are  too  rigid  to 
spring  from  the  tool,  are  nevertheless  liable  to  slight  irregulari- 
ties arising  from  imperfections  in  the  slides  of  the  lathe  in 
which  they  are  turned,  hard  and  soft  places  in  the  metal,  and 
also  the  wear  of  the  tool,  which,  although  small,  is  quite  appre- 
ciable in  works  of  moderate  length.  These  circumstances  com- 
bined, render  the  attainment  of  a  perfect  cylindrical  rod  by  turn- 


1233  GRINDJNG-CLAMP    FOR    CYLINDRICAL   RODS. 

ing  a  matter  of  considerable  practical  difficulty;  and  consequently, 
it  is  usual,  after  the  work  has  been  turned  as  true  as  possible,  to 
reduce  the  minute  errors  by  grinding,  and  which,  at  the  same 
time,  serves  to  give  the  work  a  more  highly  finished  appearance. 
The  above  classes  of  work  which  only  require  a  moderate  degree 
of  accuracy  are  usually  ground  between  lead  or  tin  grinders  of 
counterpart  form,  supplied  with  emery  and  water,  or  oil,  and 
fixed  in  iron  clamps  that  supply  the  pressure,  and  serve  as 
handles  for  the  application  of  the  grinders. 

Figs.  1111,  and  1112,  represent  in  two  views  a  grinding  clamp 
suitable  for  cylindrical  rods  of  medium  size.  The  two  halves  of 
the  clamp  are  connected  at  each  end  by  two  binding  screws,  £, 
and  the  clamps  are  curved  in  the  middle,  so  that  when  they  are 
separated  about  one  quarter  of  an  inch  by  the  set  screws,  s,  they 
may  present  in  the  center  a  cylindrical  aperture  about  one  inch 
larger  in  diameter  than  the  cylinder  to  be  ground. 

FIGS.  1111.          <*-<**-& — — 


1112. 


For  casting  the  lead  grinders  within  the  iron  clamps,  the  set 
screws  are  withdrawn,  and  the  binding  screws  slackened,  so  as 
to  leave  an  opening  of  about  one  quarter  of  an  inch  between  the 
flat  faces  of  the  clamps,  which  are  then  placed  edgeways  upon  a 
flat  block,  and  a  short  cylinder  or  core  of  the  same  diameter  as 
the  cylinder  to  be  ground,  is  placed  in  the  center  of  the  circular 
aperture,  two  parallel  slips  of  wood  or  iron  sufficiently  wide  to 
be  grasped  between  the  flat  faces  of  the  clamps,  are  then  placed 
in  contact  with  the  sides  of  the  core,  so  as  to  divide  the  opening 
into  two  parts,  and  are  firmly  pinched  by  the  binding  screws. 
Melted  lead  is  now  poured  in  to  fill  up  the  cavities,  and  form 
two  grinders,  each  a  little  less  than  the  semicircle,  and  the 
cylindrical  faces  of  which  are  counterparts  of  the  metal  core. 
The  inside  surfaces  of  the  clamps  are  left  rather  rough,  in  order 
that  they  may  the  better  hold  the  lead  ;  and,  with  the  same 


GRINDING    CYLINDRICAL   RODS.  1234 


view,  a  few  radial  holes  are  sometimes  drilled  in  the  clamps,  or 
otherwise  the  edges  of  the  opening  are  chamfered  off,  in  order 
that  the  lead  may  be  cast  with  a  projection  on  each  side  to 
prevent  the  grinders  from  shifting  endways. 

To  keep  the  core  in  the  center  of  the  clamp  while  the  lead  is 
being  poured,  a  hole  is  sometimes  bored  in  the  block  upon  .which 

e  clamps  are  laid.  At  other  times  the  grinders  are  cast  at 
once  upon  the  rod  to  be  ground  ;  in  this  case  the  rod  is  fixed 
vertically  in  a  vice,  and  a  hole  is  bored  through  a  piece  of  wood, 
which  is  slipped  on  the  rod,  and  luted  with  clay  to  make  a  close 

Kint. 
In  grinding  a  long  cylindrical  rod  the  work  is  mounted  in  the 
the,  and  the  grinder  is  fitted  upon  one  part  of  the  rod  by  first 
closing  the  clamps  with  the  binding  screws  #,  the  set  screws  s  are 
then  advanced  to  partially  sustain  the  pressure  of  the  binding 
screws,  and  separate  the  clamps  just  sufficiently  to  allow  the  rod 
to  revolve  within  the  grinder,  with  as  much  friction  as  can  be 
conveniently  overcome  by  the  hands  applied  to  the  extremities 
of  the  lever  or  handle.     The  lathe  is  then  put  in  rotation,  and 
the  grinder  is  traversed  backwards  and  forwards,  throughout  the 
length  of  the  rod,  with  a  screwing  action  somewhat  as  in  boring 
a  hole  with  an  auger.     If  the  grinder  were  slowly  traversed 
straight  along  the  rod,  the  latter  would  not  be  so  uniformly 
ground,  and  when  finished  it  would  be  marked  with  rings,  partly 
owing  to  the    emery  not  being  equally  distributed   over   the 
surface  of  the  work.     The  grinder  is  first  applied  to  those  parts 
f  the  rod  which  present  the  greatest  amount  of  friction,  and 
hen  the  resistance  becomes  lessened  at  the  most  prominent 
,rts  of  its  length,  the  grinding  clamps  are  closed  upon  the  rod, 
>y  withdrawing   the   set   screws   and   tightening   the   binding 
rews.     The  clamps  thus  admit  of  being  gradually  adjusted,  so 
to  serve  almost  as  a  gage  for  the  parallelism  of  the  rod,  and 
ccessively  reduce  the  parts  of  largest  diameter,  until  the  grinder 
ides  smoothly  and  with  uniform  resistance  from  end  to  end  of 
e  cylinder. 

The  grinder  should  be  as  nearly  as  possible  the  counterpart  of 
the  desired  cylinder,  but  in  the  course  of  work  the  grinder 
becomes  irregularly  enlarged,  while  at  the  same  time  the  cylin- 
der is  gradually  although  slightly  reduced  ;  the  closing  of  the 
clamps  partially  compensates  for  the  difference  of  diameter, 

VOL.  III.  P 


1235  GRINDING  CYLINDRICAL   WORKS    IN    METAL. 


but  not  for  the  irregularity  of  wear,  and  consequently  two 
grinders  are  usually  required  for  the  completion  of  the  cylinder. 
The  principal  errors  are  removed  with  the  first,  and  when  the 
rod  has  been  rendered  tolerably  cylindrical,  and  very  nearly  of  the 
required  diameter,  a  second  grinder  is  cast  for  finishing  the  work. 

When  the  rods  are  required  to  be  of  precise  diameter,  for 
sliding  through  bearings  and  similar  purposes,  they  are  turned 
slightly  larger  than  the  finished  size,  and  gradually  reduced  by 
grinding,  until  upon  trial  they  are  found  to  fit  with  sufficient 
precision  into  the  hole  in  which  they  are  intended  to  work. 
Sometimes  brass  or  gun-metal  grinders  made  in  halves,  connected 
by  screws,  and  bored  out  to  the  exact  diameter,  are  employed 
for  the  final  adjustment  of  cylindrical  works  required  to  be  of 
definite  diameter,  but  the  method  is  scarcely  trustworthy,  as 
the  grinders  are  themselves  rapidly  abraded,  and  soon  become 
enlarged,  unless  they  are  very  sparingly  employed. 

Short  cylinders  are  in  many  cases  ground  by  hand  instead  of 
in  the  lathe,  the  work  is  then  fixed  horizontally  in  the  vice,  and 
the  workman  stands  in  front  of  the  cylinder,  and  twists  the 
grinder  about  half  way  round  backwards  and  forwards,  and  at 
the  same  time  traverses  it  to  and  fro  lengthways  of  the  cylinder, 
varying  the  direction  of  the  stroke  as  much  as  possible  every 
time,  and  occasionally  twisting  the  cylinder  partly  round  in  the 
vice,  in  order  to  expose  it  more  equally  to  the  action  of  the 
grinder,  which  is  fitted  upon  the  cylinder,  and  applied  to  reduce 
the  high  points  in  succession,  just  the  same  as  in  the  lathe 
process.  This  method  is  less  rapid  than  grinding  in  the  lathe, 
but  is  more  under  control,  as  the  resistance  offered  by  trifling 
irregularities,  is  more  easily  appreciated  when  the  work  is  at 
rest,  than  when  it  is  revolving,  and  from  the  constant  change  of 
the  path  of  the  grinder,  the  cylinder  is  less  liable  to  be  marked 
with  rings. 

When  the  cylinder  terminates  at  the  one  end  in  a  collar  or 
projection,  it  is  rather  difficult  to  grind  the  work  square  in  the 
corner,  partly  owing  to  the  angle  of  the  grinder  being  worn 
away.  In  this  case  tin  is  generally  used  instead  of  lead  for  the 
grinder,  which  is  also  made  narrow  in  order  to  allow  of  as  much 
of  the  traversing  or  screwing  action  as  possible,  and  partly 
avoid  the  liability  of  the  grinder  to  become  more  enlarged  at 
the  ends,  than  in  the  middle. 


GRINDING   CYLINDRICAL   WORKS    IN   METAL.  1236 


Large  cylindrical  works,  such  as  rollers,  present  too  much 
surface  friction  to  be  ground  between  clamps,  and  for  those 
purposes  which  only  require  moderate  accuracy,  the  works  are 
left  sufficiently  true  from  the  lathe,  and  the  surfaces  are  polished 
as  explained  on  page  1072.  Works  requiring  a  little  more 
accuracy  are  sometimes  smoothed  with  a  grinder,  made  by 
casting  a  lump  of  lead  upon  the  cylinder  to  embrace  about  one- 
third  of  its  circumference,  and  weighing  from  one  to  two 
hundred  weight,  a  bar  of  iron  3  or  4  feet  long  is  inserted  in  the 
loam  mould  at  the  time  of  casting,  in  order  to  serve  as  the 
handle.  The  roller  is  made  to  revolve  in  the  lathe,  and  the 
grinder,  mounted  upon  the  roller,  is  traversed  backwards  and 
forwards  by  the  handles,  the  weight  of  the  grinder  supplying  the 
pressure. 

Many  cylindrical  works,  such  as  lathe  mandrels,  gages  for 
the  diameters  of  holes,  flatting  rollers  for  thin  gold  wire,  and 
other  similar  objects,  that  are  required  to  possess  considerable 
accuracy  and  durability,  are  made  of  steel,  and  afterwards  har- 
dened, in  which  latter  process  they  are  liable  to  become  distorted, 
as  explained  in  Vol.  I.  Chap.  XII.  Sect.  IV. 

The  above  class  of  works,  which  require  the  greatest  possible 
exactness  of  form,  are  usually  ground  before  hardening,  with  the 
clamps,  fig.  1112,  but  which  method  is  not  sufficiently  accurate 
for  the  final  correction  of  the  best  works,  as  the  grinders  have  a 
constant  tendency  to  wear  of  an  oval  figure,  and  also  to  become 
rounded  in  the  direction  of  their  length,  from  the  outer  edges 
being  more  rapidly  worn  than  the  middle,  this  partly  arises 
from  the  absence  of  a  sufficient  guide  to  ensure  the  grinder  being 
traversed  parallel  to  the  axis  of  the  cylinder,  as  the  shortness  of 
the  grinder  allows  the  handles  of  the  clamp  to  be  imperceptibly 
twisted  from  the  square  position,  in  opposite  directions  with 
every  stroke. 

To  avoid  this  liability  as  much  as  possible,  in  works  requiring 
tolerable  exactness,  the  grinder  is  made  as  long  as  admissible, 
and  the  handles  very  short,  in  order  to  reduce  the  leverage  as 
much  as  possible,  the  finishing  clamps  being  sometimes  no  longer 
than  is  required  for  the  binding  screws,  which  are  only  tightened 
so  far  that  the  grinder  just  touches  the  highest  points  of  the 
cylinder,  and  allows  of  its  being  traversed  with  very  moderate 
force,  so  that  small  inequalities  may  be  detected  by  the  sense  of 


1237     FIXED  AND  REVOLVING  GRINDERS  FOR  CYLINDRICAL  WORKS. 


feeling,  and  in  this  manner  a  sufficient  approach  to  correctness 
for  many  works  is  readily  attained.  But  although  with  careful 
management  the  work  may  be  made  tolerably  circular  by  this 
method,  it  is  deficient  of  any  correctional  process  that  can  be 
relied  upon  for  the  absolute  straightness  of  the  cylinder. 

A  more  accurate  method  for  the  best  works,  is  to  mount  the 
cylinder  upon  the  lathe,  and  apply  a  fixed  grinder  in  the  sliding 
rest,  exactly  like  a  blunt  turning  tool.  The  grinder  is  made  of 
lead,  copper  or  iron,  supplied  with  fine  emery,  and  adjusted  so  as 
just  to  touch  the  highest  points  of  the  cylinder  as  it  revolves 
with  moderate  velocity.  The  grinder  is  traversed  from  end  to 
end  of  the  cylinder  by  the  sliding  rest,  and  as  the  highest  points 
are  gradually  reduced,  the  grinder  is  set  forward  to  remove  the 
next  series  of  prominencies  and  so  on.  By  this  method  the 
true  circular  form  may  be  at  once  attained,  and  the  parallelism 
of  the  cylinder  will  depend  upon  the  perfection  of  the  slide,  and 
the  accuracy  with  which  it  is  adjusted.  In  some  few  instances 
a  diamond  point  mounted  in  the  sliding  rest,  and  traversed  with 
a  very  slow  motion,  has  been  similarly  employed,  for  correcting 
hardened  steel  rollers  requiring  great  accuracy,  but  the  method 
is  tedious,  and  scarcely  better  than  the  fixed  grinder  supplied 
with  emery. 

Another  method  very  nearly  as  accurate  and  much  more  expe- 
ditious than  the  fixed  grinder,  is  the  analogous  employment  of  a 
rapidly  revolving  lap,  mounted  on  the  sliding  rest,  and  gradually 
traversed  along  the  cylinder,  which  at  the  same  time  slowly 
revolves  upon  the  lathe.  The  best  lathe  mandrels  are  frequently 
corrected  in  this  manner  after  hardening.  The  iron  or  copper 
laps  generally  employed  for  this  purpose  measure  from  6  to  9 
inches  diameter,  and  about  five-eighths  of  an  inch  thick ;  they 
are  driven  at  a  velocity  of  about  SCO  to  400  revolutions  per 
minute,  and  the  mandrel  makes  about  20  revolutions  in  the 
same  time. 


The  cylindrical  rollers  used  in  paper-making  machinery,  for 
pressing  the  single  sheet  of  paper  as  it  is  produced  by  the 
machine,  require  that  the  two  surfaces  should  fit  each  other  with 
great  accuracy,  in  order  that  the  rollers  may  act  uniformly  upon 
the  paper,  and  the  surfaces  at  the  same  time  are  required  to  be 


GRINDING    CYLINDRICAL    ROLLERS    FOR    PAPER    MAKING.       1238 

very  smooth,  that  they  may  impart  a  finished  surface  to  the 
paper. 

The  ordinary  methods  of  grinding  cylindrical  surfaces  with 
emery,  are  not  sufficiently  exact  for  the  production  of  these  rollers, 
as  the  leading  source  of  error  in  all  grinding  processes,  namely, 
the  unequal  distribution  of  the  abrading  powder  arising  from  the 
absence  of  control,  allows  the  loose  emery  to  accumulate  upon 
the  lowest  points,  and,  consequently,  after  a  certain  approach  to 
accuracy  has  been  attained,  the  further  continuance  of  the 
grinding  leads  to  the  depreciation  of  the  surface  by  the  continual 
introduction  of  new  errors.  The  impossibility  of  producing  by 
these  means  large  cylindrical  rollers,  sometimes  required  to  be  as 
much  as  6  feet  long  and  18  inches  diameter,  with  sufficient  accu- 
racy to  press  uniformly  a  single  sheet  of  the  thinnest  paper,  has 
led,  after  numerous  tedious  and  expensive  experiments,  to  the 
final  abandonment  of  all  abrading  powder,  and  the  required 
accuracy  of  contact  is  attained  by  the  simple  friction  of  the 
surfaces  of  the  rollers  rubbing  upon  each  other,  plain  water  being 
plentifully  supplied  to  lubricate  the  surfaces,  and  prevent  their 
heating  and  tearing  each  other. 

The  rollers  are  first  turned  as  truly  cylindrical  as  possible  in 
the  lathe,  and  tested  for  parallelism  by  carefully  measuring  the 
circumference  at  various  parts,  with  a  thin  copper  wire  wrapped 
around  the  cylinder,  a  more  exact  test  than  gaging  the  diameter, 
the  journals  of  the  cylinder  are  turned  at  the  same  time,  in  order 
to  ensure  their  being  concentric. 

The  rollers  are  next  mounted  on  their  own  bearings,  in  a  frame 
similar  to  that  in  which  they  are  to  be  employed,  and  their 
surfaces  are  carefully  adjusted  to  each  other,  the  bearings  of  the 
one  roller  being  fixed,  and  those  of  the  other  placed  under  the 
control  of  a  screw  adjustment,  that  admits  of  the  rollers  being 
closed  upon  each  other  so  that  the  highest  points  alone  just 
touch.  The  rollers  are  now  examined  to  ascertain  whether  they 
fit  each  other  tolerably  well  throughout  their  length,  as  when 
both  rollers  have  been  turned  in  the  same  lathe,  they  will  in  all 
probability  possess  the  same  general  error,  or  both  be  either 
concave  or  convex  in  the  direction  of  their  length.  Most 
generally  long  rollers  will  be  turned  slightly  concave,  from  tho 
slide  of  the  lathe  being  more  worn  in  the  middle  by  short  works, 
and  the  two  rollers  when  placed  in  contact  will  show  double  the 


1239        GRINDING    CYLINDRICAL    ROLLERS    FOR    PAPER    MAKING. 

amount  of  error,  which  if  considerable  is  sometimes  reduced  by 
grinding  each  roller  separately,  with  a  lead  grinder  supplied  with 
emery  and  mounted  on  the  end  of  a  lever,  that  is  used  to  press 
the  grinder  in  contact  with  the  surface  of  the  cylinder,  much  the 
same  as  in  polishing  large  turned  works. 

When  the  errors  are  so  far  reduced,  that  they  cannot  be 
detected  by  the  line  of  light  between  the  cylinders,  they  are  put 
in  revolution,  and  the  one  roller  marked  slightly  with  a  piece  of 
chalk  applied  at  intervals  of  a  few  inches,  the  revolution  of  the 
rollers  transfers  the  chalk  lines  from  the  one  roller  to  the  other,  at 
those  parts  where  they  touch,  which  shows  at  a  glance  the  highest 
parts.  The  points  thus  indicated  are  successively  reduced  with 
the  grinder  until  the  rollers  fit  each  other  sufficiently  well  to 
transfer  all  the  lines  with  tolerable  regularity,  which  indicates  a 
moderate  approach  to  general  truth,  but  by  no  means  sufficient 
for  the  purpose,  as  numerous  minute  errors  will  still  remain  that 
cannot  be  detected  by  the  chalk  lines. 

The  rollers  are  now  carefully  adjusted  so  that  their  highest 
points  alone  touch  each  other,  and  the  rollers  are  driven  at 
different  velocities,  by  separate  straps  leading  to  pulleys  fixed  on 
the  axis  of  the  rollers,  which  revolve  in  the  same  direction,  so 
that  the  two  surfaces  in  contact  meet  and  pass  each  other  in 
opposite  directions,  and  the  velocities  being  different,  the  relative 
positions  of  the  rollers  are  continually  changing,  and  it  is  only 
after  many  revolutions  that  the  same  points  again  come  in 
contact. 

The  friction  of  the  two  surfaces  causes  them  mutually,  although 
slowly,  to  abrade  each  other,  and  a  constant  stream  of  water  is 
directed  upon  the  rollers,  to  lubricate  their  surfaces  and  prevent 
them  from  heating.  The  latter  is  a  point  of  considerable  im- 
portance, as  should  the  rollers  become  unequally  heated  from 
their  surfaces  being  dry,  or  from  too  high  a  velocity  being 
employed,  the  surfaces  would  not  only  be  liable  to  tear,  but  the 
irregular  expansion  of  the  metal  would  continually  introduce  new 
errors,  and  the  true  cylindrical  form  could  not  result. 

Attention  is  required  to  keep  the  rollers  in  equal  contact 
with  each  other  at  the  high  points  throughout  their  length,  and 
as  these  are  gradually  reduced,  the  rollers  are  slightly  closed 
upon  each  other  to  bring  the  next  series  of  high  points  in  con- 
tact. It  being  considered  that  if  the  rollers  were  firmly  pressed 


GRINDING    CYLINDRICAL    ROLLERS    FOR    PAPER     MAKING.        1240 


upon  each  other,  they  would  be  more  liable  to  copy  their 
mutual  irregularities,  and  also  that  the  pressure  would  be 
liable  to  cause  the  one  roller  to  follow  the  path  of  the  other,  or 
be  driven  by  their  surface  contact,  notwithstanding  the  action 
of  the  belts  on  the  driving  pulleys. 

As  the  surfaces  approach  nearer  to  perfection,  the  length  of 
contact  is  gradually  increased,  and  proportionately  greater  care 
is  required  in  the  adjustment  of  the  rollers,  to  prevent  the  friction 
becoming  so  great  as  to  tear  the  surfaces,  or  cause  increase  of 
temperature.  The  process  is  tedious,  and  requires  to  be  con- 
tinued for  several  days,  until  the  contact  of  the  surfaces  is  as 
perfect  as  possible,  throughout  the  length  of  the  rollers,  in  every 
position  in  which  they  are  brought,  by  the  continual  change  of 
their  relative  positions. 

A  very  smooth  and  polished  surface  is  produced  in  this  manner 
by  the  use  of  water  alone,  but  for  those  rollers  required  to 
possess  a  still  smoother  surface,  Messrs.  Hopkinson  and  Cope, 
(from  whose  practice  the  foregoing  particulars  have  been  derived,) 
have  adopted  the  use  of  oil  instead  of  water  for  the  last  finish, 
and  the  smoothness  of  surface  thus  produced  leaves  little  room 
for  improvement. 

A  different  method  of  carrying  out  the  principle  of  grinding 
the  rollers  together  with  water  is  sometimes  resorted  to,  in 
order  to  allow  of  the  rollers  being  subjected  to  the  same  degree 
of  pressure  during  grinding,  that  they  are  intended  to  sustain 
when  at  work,  as  it  is  occasionally  found  that  notwithstanding 
the  strength  of  the  rollers,  they  yield  slightly  beneath  great 
pressure,  so  as  to  interfere  with  the  accuracy  of  contact. 

To  avoid  this  interference  the  bearings  of  the  upper  roller 
instead  of  being  suspended  over  the  lower,  so  that  the  high 
points  of  the  two  rollers  alone  touch,  are  loaded  so  as  to  press 
the  rollers  in  contact  with  the  same  degree  of  force  that  is 
required  for  pressing  the  paper.  But .  under  this  pressure  the 
surfaces  in  contact  do  not  admit  of  being  driven  in  opposite 
directions,  because  it  is  found  that  the  two  surfaces  meeting  each 
other,  cause  so  much  friction  that  the  rollers  are  almost  certain 
to  be  torn  even  when  a  very  slow  motion  is  employed.  The 
rollers  are  therefore  driven  in  opposite  directions  at  different 
velocities,  generally  in  the  proportion  of  nearly  5  to  6,  so  that 
the  surfaces  in  contact  travel  in  the  same  direction,  but  the 


1241       GRINDING    CYLINDRICAL   ROLLERS    FOR   PAPER   MAKING, 


velocities  being  different  they  move  over  each  other  with  a 
sliding  action. 

The  adjustment  of  the  velocity  depends  principally  upon  the 
degree  of  pressure  employed,  and  the  condition  of  the  surfaces ; 
if  driven  too  rapidly  the  surfaces  are  liable  to  heat  and  tear  each 
other,  which  in  this  as  in  the  arrangement  previously  described 
is  the  principal  difficulty  to  be  contended  with. 

The  water  is  supplied  through  a  perforated  tube  extending 
the  length  of  the  rollers,  and  should  any  portion  of  the  rollers 
appear  to  be  grinding  too  rapidly,  the  action  may  be  checked 
by  stopping  up  some  of  the  holes  to  reduce  the  supply  of  water 
at  that  part,  but  which  is  not  generally  resorted  to,  owing  to 
the  risk  of  the  rollers  being  allowed  to  become  too  dry  from 
neglect  on  the  part  of  the  attendant. 

The  grinding  action  appears  to  be  principally  due  to  the  small 
particles  of  cast  iron  rubbed  off  by  the  friction,  and  which  serve 
as  the  abrading  powder.  The  progress  of  the  grinding  may  be 
expedited  at  the  commencement,  by  using  the  same  water 
repeatedly  over  again,  in  order  to  bring  a  larger  quantity  of  the 
grinding  powder  into  action,  but  towards  the  conclusion  of  the 
process  when  the  highest  finish  is  required,  clear  water  is  alone 
used. 

The  process  appears  to  be  partly  grinding  and  partly  burnish- 
ing, and  does  not  admit  of  being  indefinitely  pursued,  as  if  con- 
tinued too  long  the  surfaces  crumble  away,  which  is  also  liable 
to  occur  if  the  castings  be  unsound,  and  therefore  all  such  places 
should  be  plugged  up  with  cast  iron  of  the  same  quality  and 
hardness  as  the  rollers.  Wrought  iron  should  never  be  used  for 
the  plugging  as  it  is  but  little  acted  upon  by  the  water  grinding, 
and  the  wrought  iron  plugs  would  stand  out  beyond  the  general 
surface  of  the  rollers. 

Accuracy  of  surface  contact  is  the  object  desired  in  these 
rollers,  and  their  absolute  straightness  is  a  matter  of  secondary 
importance,  the  rollers  are  therefore  made  simply  to  revolve 
upon  their  axes,  and  are  not  at  the  same  time  traversed  through 
their  bearings,  as  this  would  be  liable  to  introduce  a  new  source 
of  error  by  wearing  the  journals  into  a  screw-like  form.  A 
small  amount  of  end  adjustment  is  however  sometimes  adopted, 
should  the  rollers  be  found  to  wear  into  rings ;  with  this  view 
the  bearings  are  so  far  separated  as  to  allow  of  a  little  end 


GRINDING    THE    CYLINDRICAL    RIMS    OF    PULLEYS.  1242 


motion  in  the  journals,  and  the  insertion  of  washers  between 
the  collars  and  bearings,  allows  of  the  rollers  being  shifted 
endways  a  small  distance  when  required.  This  adjustment  is 
however  scarcely  called  for,  as  without  it  a  pair  of  rollers  may 
be  ground  so  nearly  straight,  that  the  ordinary  test  of  a  straight 
edge  would  fail  to  detect  any  irregularity,  and  when  three  or  more 
rollers  are  ground  with  their  surfaces  in  contact,  they  mutually 

Irrect  each  other  for  straightness  as  well  as  circularity. 
The  cylindrical  rims  of  pulleys  employed  for  driving  machinery 
leather  straps  are  usually  turned  to  form  in  the  lathe,  and 
aiterwards  smoothed  with  emery  applied  on  a  stick  as  explained 
at  page  1072.  But  in  some  cases  these  pulleys  are  wrought 
into  the  cylindrical  form  by  the  ordinary  grindstone,  assisted 
by  a  little  mechanism,  after  the  same  general  method  as  that 
employed  for  grinding  superior  cylindrical  works.  In  the  case 
of  pulleys  the  grinding  is  resorted  to  not  from  any  superiority 
in  the  method,  but  solely  from  motives  of  economy,  the  grind- 
stone being  more  rapid  in  its  action  than  the  turning  tool,  when 
the  object  is  merely  to  produce  a  level  surface,  without  removing 
a  greater  bulk  of  the  material  than  is  necessary  for  that  purpose, 
as  the  turning  tool  requires  to  penetrate  sufficiently  deep  into 
the  metal  to  remove  the  outer  hard  crust  left  in  casting,  as 
explained  on  page  375,  Vol.  I.  The  action  of  the  grindstone  is 
however  little  influenced  by  the  hard  crust,  and  consequently  a 
much  smaller  quantity  of  material  has  to  to  be  removed  by 
grinding  to  produce  the  cylindrical  form. 

In  Mr.  James  Whit  claw's  machine  for  grinding  pulleys,*  the 
grindstone  of  about  4  feet  diameter  is  mounted  in  fixed  bearings 
as  usual,  and  revolves  about  1 80  times  per  minute,  the  pulley  to 
be  ground  is  fixed  upon  a  mandrel  parallel  to  the  axis  of  the 
grindstone,  and  makes  about  130  revolutions  in  the  minute  in 
the  same  direction  as  the  grindstone,  so  that  when  the  opposite 
edges  of  the  pulley  and  grindstone  are  brought  into  contact,  the 
two  surfaces  rub  upon  each  other  at  their  combined  velocities, 
and  at  the  same  time  the  pulley  is  reciprocated  a  few  inches 

*  Described  in  a  communication  to  the  Royal  Scottish  Society  of  Arts,  1838. 
See  Trans.  Roy.  Scot.  Soc.  of  Arts.,  Vol.  I.,  page  235. 


1243    WHITELAW'S  MACHINE  FOR  GRINDING  THE  RIMS  OF  PULLEYS. 


backwards  and  forwards  across  the  face  of  the  grindstone,  to 
equalise  the  wear  of  the  latter,  and  ensure  the  cylindrical  form 
of  the  pulley. 


Fm.  1113. 


This  machine  is  shown  in  plan  in  fig.  1 1 13,  in  which  a  represents 
the  grindstone,  and  b  the  pulley  to  be  ground,  the  pulley  is 
mounted  upon  the  mandrel  c,  which  for  the  convenience  of  easy 
removal  is  fitted  by  a  key  into  the  spindle  J,  at  the  one  end,  and 
works  through  a  plummer  block  e,  at  the  other.  The  spindle  d 
is  fitted  in  bearings  fixed  on  the  frame  f,  which  together  with  the 
plummer  block  e,  are  traversed  simultaneously  on  longitudinal 
slide  bars  #,  by  three  screws  of  equal  pitch,  each  communicating 
by  a  pair  of  bevil  wheels  with  a  transverse  rod  7i,  having  a  wheel 
on  its  end  to  be  moved  by  hand.  By  this  arrangement  the 
pulley  admits  of  being  gradually  advanced  in  a  parallel  line,  to 
keep  its  edge  in  contact  with  the  stone  as  the  grinding  proceeds. 

The  spindle  upon  which  the  pulley  is  mounted,  is  reciprocated 
to  and  fro  through  its  bearings,  by  means  of  a  crank  on  the  end 
of  the  shaft  z,  which  is  driven  by  a  bevil  wheel  leading  to  a 
pinion  fixed  on  the  axis  of  the  grindstone.  The  pin  of  the  crank 
on  the  shaft  £,  works  in  a  brass  that  slides  in  a  perpendicular 
groove  in  the  frame  j\  which  is  fitted  between  collars  on  the 
spindle  carrying  the  pulley,  and  slides  upon  a  parallel  guide  .rod 
at  the  back.  The  revolution  of  the  crank  pin  traverses  the 
frame  J,  and  the  pulley  spindle  connected  with  it,  and  as  the 


MACHINES    FOR    GRINDING    THE    RIMS    OF    PULLEYS.  1244 


crank  pin  is  fitted  in  a  groove  that  admits  of  its  being  placed  at 
any  distance  from  the  center,  the  amount  of  reciprocation  may 
be  readily  adjusted  to  suit  the  width  of  the  pulley.  To  allow  of 
the  crank  being  traversed  longitudinally  with  the  frame  /  carry- 
ing the  spindle  of  the  pulley,  the  crank  shaft  i  is  made  to  slide 
through  the  hollow  axis  of  the  bevil  wheel,  which  is  bored  out  of 
the  proper  diameter,  and  provided  with  a  feather,  that  enters  a 
groove  extending  throughout  the  length  of  the  shaft,  to  cause  its 
rotation. 

Mr.  Whitelaw  also  proposed  another  machine  for  grinding 
pulleys  that  are  required  to  be  rounded  upon  the  edge  instead  of 
being  cylindrical,  this  machine  is  very  similar  in  its  general 
arrangement  to  fig.  1113,  but  instead  of  the  spindle  carrying  the 
pulley,  being  reciprocated  in  a  straight  line  through  the  bearings, 
the  revolving  spindle  is  mounted  in  a  swing  frame  having  vertical 
pivots.  The  frame  is  swung  horizontally  backwards  and  for- 
wards by  an  eccentric,  so  that  the  edge  of  the  pulley  in  contact 
with  the  stone  describes  the  arc  of  a  circle,  of  which  the  vertical 
pivots  are  the  center,  and  as  the  latter  are  fitted  into  grooves  in 
the  top  and  bottom  of  the  swing  frame,  they  admit  of  being 
adjusted  to  give  any  required  degree  of  curvature  to  the  edge  of 
the  pulley.  The  length  of  traverse  of  the  swing  frame  is  adjusted 
by  attaching  the  connecting  rod  leading  from  the  eccentric,  at 
different  distances  from  the  center  of  motion. 

In  another  machine  for  grinding  cylindrical  pulleys  made  by 
Messrs.  Randolph  Elliot  &  Co.  of  Glasgow,*  the  pulley  to  be 
ground  is  mounted  on  a  mandrel  revolving  with  moderate  velo- 
city in  fixed  bearings,  and  the  grindstone  which  revolves  with 
considerable  rapidity  is  slowly  traversed  across  the  face  of  the 
pulley,  by  means  of  a  screw  passing  through  the  hollow  shaft  of 
the  grindstone,  and  driven  by  a  system  of  differential  wheels 
mounted  on  a  sliding  frame,  that  is  shifted  to  and  fro  by  hand, 
in  order  to  reverse  the  motion  of  the  screw.  The  grindstone  is 
fitted  in  the  center  with  a  cylindrical  bearing  that  slides  upon 
the  shaft,  and  the  traverse  motion  is  communicated  from  the 
screw  to  the  grindstone  by  means  of  a  nut  having  two  flanges, 
that  pass  through  longitudinal  grooves  in  the  hollow  shaft,  and 
are  firmly  fixed  to  the  cylindrical  bearing  of  the  grindstone. 

*  See  Practical  Mechanic  and  Engineers'  Magazine,  Vol.  IV.  p.  73. 


1245  SOLID    GRINDERS    FOR    CYLINDRICAL    HOLES. 


The  bearings  of  the  spindle  carrying  the  pulley  to  be  ground, 
are  attached  to  a  frame  sliding  horizontally,  and  adjusted  by  a 
single  screw  to  bring  the  edge  of  the  pulley  in  contact  with  the 
stone  ;  and  to  keep  the  pressure  uniform  notwithstanding  any 
trifling  irregularities  of  the  stone,  a  spring  is  introduced  between 
the  adjusting  screw  and  sliding  frame.  As  in  Mr.  Whitelaw's 
machine  the  axis  of  the  grindstone  and  pulley  are  placed  parallel 
to  each  other,  and  are  driven  in  the  same  direction,  so  as  to 
combine  the  velocity  of  the  two  surfaces. 


Internal  cylindrical  surfaces  such  as  the  bearings  for  spindles, 
and  similar  works  in  iron  and  steel,  are  ground  with  cylindrical 
grinders,  generally  of  lead  or  tin,  but  sometimes  for  greater 
durability  and  exactness  brass  or  iron  are  employed.  The 
grinders  are  in  general  made  as  solid  cylinders  of  the  required 
diameter,  and  a  succession  of  grinders  are  employed  each  a  little 
larger  than  the  preceding,  but  sometimes  the  grinders  are  made 
with  a  small  power  of  expansion  in  order  to  avoid  the  necessity 
for  several  grinders  when  the  hole  has  to  be  materially  enlarged. 

Figs.  1114  to  1117  represent  some  of  the  most  usual  forms  of 
grinders  for  internal  cylinders. 

FIG.  1114. 


Fig.  1114  consists  simply  of  a  bar  of  iron,  upon  the  middle  of 
which  a  lump  of  lead  is  cast  and  turned  to  the  suitable  diameter. 
This  form  of  grinder  is  the  most  generally  employed  for  cylin- 
drical holes  that  pass  entirely  through  the  object,  the  iron  bar 
upon  which  the  grinder  is  cast,  is  made  much  longer  than  the 
hole  to  be  ground,  in  order  that  it  may  be  traversed  endways 
through  the  hole  to  equalize  its  diameter,  and  prevent  the  forma- 
tion of  rings.  When  the  hole  is  long  and  has  merely  to  be 
corrected  for  trifling  irregularities,  the  object  is  fixed  horizon- 
tally in  the  vice,  and  the  central  rod  of  the  grinder  is  grasped  in 
a  diestock  or  fitted  with  a  pulley  to  serve  as  the  handle.  The 
grinder  is  then  charged  with  emery,  inserted  in  the  hole,  and 
worked  backwards  and  forwards  with  a  screw-like  motion,  the 
same  as  in  grinding  an  external  cylinder  by  hand  ;  to  facilitate 


SOLID    GRINDERS    FOR    CYLINDRICAL    HOLES.  1246 

the  first  entry  of  the  grinder,  it  is  made  slightly  taper  at  the 
front  end.  Small  grinders  soon  become  reduced  in  diameter  by 
use,  sometimes  to  compensate  for  the  wear  the  grinder  is  laid 
ipon  the  lathe-bearers  or  other  support,  and  a  few  light  blows 
>f  a  hammer  are  given  along  one  side  to  spread  the  metal  out  to 
larger  diameter.  The  two  flat  faces  thus  made  along  the  sides 
of  the  grinder  also  serve  to  allow  of  the  escape  of  the  surplus 
emery,  and  with  this  view  large  grinders  are  frequently  made  with 
a  few  grooves  along  the  sides. 

When  the  hole  is  so  short  that  it  would  not  serve  as  a  guide 
for  the  grinder,  the  latter  is  mounted  to  revolve  in  a  lathe,  and 
the  work  held  by  the  hands  is  traversed  endways  on  the  grinder, 
and  at  intervals  is  allowed  to  be  partly  carried  round  by  the 
friction,  so  as  continually  to  place  the  work  in  different  angular 
positions,  which  serve  to  prevent  the  hole  from  being  ground 
either  oblique,  or  more  on  one  side  than  the  other.  With  very 
short  holes,  care  is  required  to  traverse  the  work  quite  square  on 
the  grinder,  as  if  it  be  twisted  in  the  direction  of  the  hole,  the 
latter  will  be  ground  larger  at  the  ends  than  in  the  middle. 

In  all  cases  of  grinding  cylindrical  holes,  there  is  great  risk 
of  enlarging  the  two  ends,  partly  owing  to  the  work  being 
twisted,  and  partly  to  the  emery  cutting  more  keenly  on  its  first 
entry  into  the  hole,  and  becoming  crushed  before  it  reaches  the 
middle.  This  evil  is  sometimes  partly  avoided  by  making  the 
grinder  much  shorter  than  the  cylinder,  the  grinder  may  then  be 
applied  to  the  middle  of  the  hole  for  a  longer  period.  The 
grinding  of  long  holes  is  at  all  times  however  a  process  of  con- 
siderable uncertainty,  from  the  absence  of  any  guide  for  the 
straightness  of  the  work,  and  consequently,  except  for  hardened 
steel,  the  principal  reliance  for  accuracy  is  placed  upon  the  boring 
and  broaching  tools,  and  a  slight  grinding  is  only  occasionally 
resorted  to  for  the  purpose  of  smoothing  the  surfaces  or  fitting 
cylindrical  works  together. 

Fig.  1115  is  used  for  grinding  two  cylindrical  holes  of  unequal 

FIG.  1115. 


diameter  on  the  same  line,  as  in  the  case  of  a  screw  mandrel 
lathe  head,  the  front  bearing  of  which  is  usually  made  of  a  larger 


1247  EXPANDING   GRINDER   FOR   CYLINDRICAL   HOLES. 

diameter  than  that  at  the  back,  and  both  are  made  cylindrical  in 
order  to  allow  of  the  longitudinal  traverse  of  the  mandrel 
through  the  bearings  in  cutting  a  screw.  Both  holes  are  ground 
at  the  same  time,  as  the  distance  between  the  bearings  causes 
them  to  serve  as  a  guide  to  ensure  the  holes  being  ground 
parallel  to  each  other.  For  the  same  reason  when  holes  of 
equal  diameter  have  to  be  ground  for  the  reception  of  a  cylin- 
drical rod  or  shaft,  the  grinder  is  made  sufficiently  long  to 
grind  both  holes  at  the  one  process ;  and  in  a  similar  manner 
when  one  hole  only  has  to  be  ground,  advantage  is  taken  of  any 
hole  in  the  same  line  that  may  be  used  as  a  guide,  and  the 
grinder  is  made  with  a  cylinder  to  fit  the  second  hole,  which 
is  not  supplied  with  emery. 

The  grinder  fig.  1116  is  made  in  two  halves  to  allow  of  the 
power  of  expansion,  it  consists  of  two  semicylindrical  rods  of 

FIG.  1116. 


iron,  fitted  to  each  other  either  by  steady  pins,  or  two  projec- 
tions at  the  end  of  the  one  bar,  within  which  the  second  bar  is 
fitted.  They  are  held  together  by  3  or  4  binding  screws,  placed 
at  equal  distances,  passing  freely  through  the  one  bar  and  tapped 
into  the  other  for  the  purpose  of  closing  the  grinder  and  reduc- 
ing its  diameter.  The  bars  are  separated  by  intermediate  set 
screws,  tapped  through  the  one  bar  and  bearing  against  the 
opposite.  The  lead  to  constitute  the  grinder  is  cast  upon  the 
bars  in  much  the  same  manner  as  for  the  grinding  clamps,  fig. 
1112,  two  thin  slips  of  wood  being  inserted  between  the  bars  to 
divide  the  mould  in  two  parts. 

The  mould  for  casting  cylindrical  grinders  is  frequently  a  block 
of  wood  bored  with  a  hole  of  the  required  diameter,  but  some- 
times a  temporary  mould  is  made  of  a  sheet  of  stout  paper 
wrapped  around  a  cylinder  of  suitable  size,  and   bound  witl 
string ;  the  cylinder  is  afterwards  removed.     The  lead  should  b< 
only  of  a  moderate  heat  at  the  time  of  pouring,  or  the  casting 
will  be  liable  to  be  honey-combed,  or  filled  with  air  bubbles, 
if  the  mould  be  quite  dry,  and  if  it  be  damp,  the  fluid  metal  maj 


SPRING    GRINDER    FOR    CYLINDRICAL    HOLES.  1248 

be  forcibly  driven  out.  The  heat  of  the  melted  lead  is  therefore 
tested  with  a  piece  of  paper  thrust  below  the  surface,  and  when 
it  is  cooled  just  sufficiently  to  avoid  burning  the  paper,  the  lead 
is  poured  into  the  mould,  and  when  cold  the  grinder  is  turned  to 
the  proper  diameter. 

The  spring  grinder,  fig.  J117,  is  used  for  grinding  out  short 
holes  in  works  that  admit  of  being  mounted  in  the  lathe,  and 


FIG.  1117. 


principally  for  those  holes  that  do  not  extend  entirely  through 
the  object,  and  therefore  do  not  admit  of  the  preceding  forms  of 
grinders  being  employed.  The  two  rods  of  the  grinder  when 
left  to  themselves  spring  open  like  the  blades  of  sheep  shears, 
and  thus  maintain  a  constant  pressure  upon  the  sides  of  the  hole 
in  which  they  are  inserted.  For  casting  this  grinder  the  rods 
are  tied  nearly  close  together  with  a  piece  of  string,  and  inserted 
in  a  smooth  metal  mould  of  the  same  diameter  as  the  hole  to  be 
ground,  which  itself  is  often  used  as  the  mould,  as  this  grinder  is 
usually  left  from  the  casting,  and  not  afterwards  turned;  the 
grinder  is  finally  divided  lengthways  with  a  saw. 

The  angular  manner  in  which  the  rods  separate  is  rather 
objectionable,  but  nevertheless  with  careful  management  it 
answers  moderately  well  for  holes  but  little  larger  in  diameter 
than  itself,  as  the  angular  difference  for  small  openings  is  so 
slight  as  to  be  scarcely  appreciable.  A  solid  grinder  is  sometimes 
used  for  stopped  holes,  but  whatever  form  of  grinder  may  be 
employed,  it  is  difficult,  with  small  deep  holes,  to  grind  the  work 
cylindrical  close  up  to  the  bottom  of  the  hole,  and  which  is  also 
very  liable  to  become  enlarged  at  the  open  end,  consequently  the 
grinder  is  always  required  to  be  shorter  than  the  depth  of  the 
hole  to  be  ground,  and  to  be  kept  towards  the  bottom,  the 
amount  of  end  traverse  being  only  just  sufficient  to  avoid  the 
formation  of  rings. 

The  cylinders  of  steam  engines  are  usually  considered  to  be 
left  sufficiently  smooth  from  the  boring  machines,  such  as  fig.  517, 
page  571,  Vol.  II.;  sometimes,  however,  they  are  smoothed  by 


1249  GRINDERS    FOR    SHORT    CYLINDRICAL    HOLES. 


grinding  them  with  a  heavy  mass  of  lead,  cast  upon  the  middle 
of  a  long  rod,  to  the  same  curve  as  the  inside  of  the  cylinder, 
which  itself  in  most  cases  serves  as  the  bottom  of  the  mould. 
The  cylinder  is  laid  on  its  side,  and  the  grinder  supplied  with 
emery  and  oil  is  traversed  backwards  and  forwards  by  hand,  the 
cylinder  being  occasionally  twisted  round  so  as  to  bring  every 
portion  successively  beneath  the  grinder. 

For  holes  of  moderate  length  requiring  considerable  accuracy, 
the  grinder  of  the  same  diameter  as  the  required  hole  is  in  some 
instances  mounted  on  the  end  of  a  revolving  spindle,  made  to 
slide  endways  through  cylindrical  bearings  under  the  control  of 
a  lever,  and  the  object  to  be  ground  is  fixed  quite  stationary. 
The  bearings  through  which  the  spindle  of  the  grinder  slides,  are 
required  to  be  carefully  adjusted  so  as  to  be  quite  central  and 
parallel  with  the  axis  of  the  hole,  or  the  latter  will  be  ground 
either  oval  or  oblique,  and  the  spindle  should  be  somewhat 
smaller  than  the  grinder,  to  allow  of  the  latter  being  traversed 
entirely  through  the  hole  to  equalize  the  diameter. 

Short  cylindrical  holes,  such  as  ring  gages  for  the  diameters 
of  works,  admit  of  being  very  accurately  ground  by  mounting  the 
work  to  revolve  rapidly  in  the  lathe,  and  applying  a  fixed  grinder 
of  smaller  diameter  than  the  hole,  held  in  the  slide  rest,  and 
employed  exactly  in  the  counterpart  manner  to  the  fixed  grinder 
for  external  cylinders  described  on  page  1237.  Sometimes  the 
grinder  is  made  of  soft  iron  or  copper,  but  a  circular  lump  of  lead 
cast  on  the  end  of  a  bar  of  iron  usually  serves  as  the  grinder,  it 
is  mounted  in  the  slide  rest,  which  is  carefully  adjusted  as  for 
turning  a  cylinder,  and  the  grinder  supplied  with  emery  is 
brought  in  contact  with  one  side  of  the  hole,  traversed  entirely 
through  it,  and  gradually  advanced  sideways  to  reduce  the 
high  points  in  succession,  and  enlarge  the  hole  exactly  to  the 
required  size. 


External  and  internal  cylinders  are  frequently  fitted  together 
by  grinding  them  in  contact  for  the  final  adjustment.  When 
the  works  are  of  hardened  steel,  they  are  first  separately  cor- 
rected for  the  distortion  of  hardening,  and  brought  so  near  to 
the  same  size,  that  the  cylinder  will  just  enter  the  hole  about 
one-eighth  of  an  inch  with  stiff  friction.  A  small  quantity  of 


FITTING    CYLINDRICAL   WORKS    BY    GRINDING.  1250 


the  finest  flour  emery  mixed  with  a  little  oil  is  then 

over  both  surfaces,  and  the  cylinder  is  gradually  worked  in,  first 

with  a  circular  motion  only,  until  it  is  entered  about  half  an  inch, 

and  then  with  a  screwing  action  backwards  and  forwards,  just  as 

in  grinding  out  the  hole  with  a  solid  grinder.     A  pulley  or  a 

double-ended  lever  fixed  on  the  end  of  the  cylinder  serves  as  the 

handle. 

It  is  necessary  to  keep  the  surfaces  plentifully  supplied  with 
emery  and  oil,  as  should  they  be  allowed  to  become  dry,  they 
would  be  liable  to  heat  from  the  friction,  which  then  becomes  so 
great  as  to  tear  the  surfaces  of  the  metal,  and  in  extreme  cases 
will  even  cause  them  to  hold  so  firmly  together  that  they  can 
only  be  separated  by  blows  of  a  hammer  applied  on  the  end  of 
the  cylinder,  to  the  evident  destruction  of  the  cylindrical 
surfaces.  The  grinding  with  emery  is  only  continued  until  the 
cylinder  will  just  slide  through  the  hole  with  uniform  resistance; 
the  surfaces  are  then  thoroughly  cleaned,  and  worked  in  the 
same  manner  for  a  short  time  with  oil  alone,  which  serves  to 
remove  the  last  traces  of  the  emery  and  put  a  final  polish  on  the 
work. 

When  one  cylinder  has  to  be  ground  into  two  holes,  as  for  the 
bearings  of  a  screw  mandrel  lathe,  the  two  holes  are  first  cor- 
rected with  the  grinder  at  the  one  process,  as  stated  on  page 
]  247,  but  the  mandrel  itself  is  ground  into  each  hole  separately, 
as  a  very  small  amount  of  grinding  suffices  to  fit  the  two  cylin- 
drical surfaces  together  when  properly  prepared ;  and  if  the 
mandrel  were  ground  into  both  holes  at  the  same  time,  the 
accuracy  of  fitting  could  not  be  so  delicately  felt,  and  in  all 
probability  one  of  the  holes  would  be  ground  so  far  larger  than 
the  cylinder  as  to  allow  of  a  little  side  play  or  shake  in  the 
fitting. 

Emery  may  be  employed  for  grinding  together  works  of  har- 
dened steel  without  risk  of  the  grinding  powder  becoming 
embedded  in  the  surfaces  of  the  work,  as  the  hardness  of  the 
steel  will  not  allow  the  emery  to  penetrate  sufficiently  deep  to 
be  permanently  retained.  With  soft  iron  more  care  is  required 
to  entirely  remove  the  last  particles  of  emery,  which  if  permitted 
to  remain  would  convert  the  rubbing  surfaces  into  grinders,  and 
they  would  mutually  abrade  each  other,  to  the  rapid  destruction 
of  the  fitting.  For  this  reason  emery  is  rejected  for  grinding 


VOL.  III. 


1251       THE  PRODUCTION   OF    CONICAL  SURFACES  BY  ABRASION. 

together  brass  works,  and  pumice-stone  powder  is  employed,  as 
from  its  greater  softness  and  friability  it  is  less  liable  to  become 
embedded  in  the  metal,  and  may  be  washed  away  with  oil.  But 
in  all  cases  the  grinding  together  of  soft  metals  should  be 
avoided  as  much  as  possible,  and  when  resorted  to,  the  grinding 
powder  should  be  afterwards  thoroughly  removed  from  the 
rubbing  surfaces. 


SECT.    III. THE    PRODUCTION    OF    CONICAL    SURFACES    BY   ABRASION. 

CONICAL  surfaces  are  ground  after  the  same  general  methods 
as  cylindrical  surfaces,  and  with  grinders  of  nearly  the  same 
general  forms,  the  principal  differences  being  that  the  grinders 
are  made  conical  instead  of  cylindrical,  and  that  they  do  not 
admit  of  being  traversed  through  each  other  like  cylinders  to 
distribute  and  correct  the  errors  of  the  grinder  itself,  and  conse- 
quently in  grinding  cones  the  accuracy  of  the  result  depends 
entirely  upon  the  truth  of  the  grinder,  which  under  the  most 
favourable  circumstances  transfers  nearly  all  its  errors  to  the 
work. 

Unlike  cylindrical  works,  conical  surfaces  are  not  usually 
ground  for  the  correction  of  the  trifling  errors  of  turning,  partly 
because  they  are  mostly  short  in  proportion  to  their  diameter,  and 
therefore  but  little  liable  to  spring  away  from  the  tool,  the  prin- 
cipal source  of  error  in  turning  long  cylinders,  and  partly  because 
the  ordinary  methods  of  grinding  cones  are  less  perfect  than 
the  methods  of  grinding  cylinders,  as  the  conical  grinders  depend 
entirely  upon  the  turning  lathe  for  their  accuracy,  and  conse- 
quently when  the  material  is  sufficiently  yielding  to  allow  of  the 
action  of  cutting  tools,  the  surfaces  may  be  thus  produced  more 
correctly  than  by  grinding,  which  in  this  case  is  principally 
employed  for  producing  accuracy  of  contact  between  two  cones 
by  grinding  them  together,  and  not  for  improving  the  general 
truth  of  either. 

Works  in  hardened  steel  are  necessarily  corrected  for 
accuracy  of  form  by  grinding,  in  order  to  remove  the  distortion 
occasioned  by  hardening ;  but  in  this  case  the  cones,  whether 
external  or  internal,  are  prepared  exactly  to  the  angle,  and  only 
slightly  larger  in  diameter  than  the  required  size,  by  turning 
them  in  the  lathe  while  soft,  so  as  to  leave  but  a  very  trifling 


GRINDERS    FOR    EXTERNAL    CONES.  1252 


amount  of  correction  to  be  effected  by  grinding.  Internal  cones 
in  objects  that  do  not  admit  of  being  conveniently  chucked,  are 
prepared  with  the  taper  broaches,  or  revolving  cutters,  described 
in  Chap.  XXV.,  Vol,  II.,  which  under  proper  management  pro- 
duce very  accurate  and  smooth  surfaces. 

The  grinding  clamps  for  cylinders,  fig.  1112,  are  also  very 
generally  employed  for  external  cones ;  the  grinder  is  cast  in 
the  same  manner,  in  two  halves,  either  upon  the  cone  itself  or 
upon  one  of  the  same  angle  and  a  little  smaller  diameter.  The 
grinder,  if  cast  of  the  same  length  as  the  cone,  is  liable  to  round 
off  the  smaller  end,  from  this  being  more  constantly  exposed  to 
the  grinding  action,  and  therefore  the  grinder  is  usually  made  a 
trifle  shorter  than  the  cone.  The  spring  grinder,  fig.  1118,  is  also 
much  used  for  small  cones;  it  is  very  nearly  a  counterpart 
of  the  grinder,  fig.  1117,  for  internal  cylinders,  the  principal 
difference  being,  that  at  the  opposite  extremity  to  the  spring  it 
is  bowed  out  near  the  ends  for  the  reception  of  the  grinder,  and 
beyond  this  enlargement  a  binding  screw  is  added,  for  closing 
the  grinder  gradually  upon  the  cone,  and  which  at  the  same 
time  serves  to  prevent  the  rods  from  springing  sideways. 


FIGS.  1118. 


1119. 


In  grinding  the  external  cone  the  work  in  almost  all  cases 
revolves  in  the  lathe,  and  the  grinder  charged  with  emery  and 
water  is  held  in  the  hands.  The  grinder  is  gradually  twisted 
round  to  different  positions,  and  continually  traversed  endways  a 
small  distance,  according  to  the  length  and  acuteness  of  the  cone. 
The  object  of  the  short  traversing  motion  is  to  distribute  the 
emery  uniformly  and  to  keep  the  particles  constantly  shifting  to 
different  parts  of  the  grinder,  as  if  they  were  allowed  to  remain 
in  the  same  position  they  /would  be  liable  to  mark  the  work  with 
rings.  On  this  account  much  less  force  is  applied  in  grinding 

Q2 


1253  GRINDING    EXTERNAL    CONES. 


cones  than  cylinders,  and  the  grinder  is  lightly  held  in  an 
elastic  manner  so  as  to  permit  the  emery  to  roll  over  between 
the  work  and  grinder. 

At  the  commencement  of  the  process  the  grinder  should  be 
somewhat  smaller  in  diameter  than  the  required  cone,  so  as  to 
allow  for  a  little  enlargement  of  the  grinder,  as  well  as  the 
reduction  of  the  cone,  which  latter  should  at  first  only  enter  the 
grinder  for  about  three  quarters  to  seven-eighths  of  its  length, 
according  to  the  acuteness  of  the  cone.  The  abrasion  of  the 
two  surfaces  allows  the  grinder  gradually  to  advance  towards 
the  larger  end  of  the  cone,  and  as  this  is  approached  the  grinder 
is  from  time  to  time  slightly  closed,  to  compensate  somewhat 
for  the  wear.  As  the  work  progresses  towards  completion, 
increased  attention  is  required  to  the  condition  of  the  grinder, 
and  when  it  becomes  so  far  worn  as  to  mark  the  work  with  rings, 
or  that  the  smaller  end  of  the  cone  protrudes,  a  new  grinder  is 
cast  for  the  completion  of  the  work. 

In  the  case  of  two  cones  of  different  angles  joining  each  other 
as  in  fig.  1119,  a  form  frequently  employed  in  lathe  mandrels, 
the  grinder  cast  to  a  counterpart  form  is  first  employed  to  grind 
both  cones  at  the  same  time  in  order  to  ensure  their  being  con- 
centric with  each  other.  The  long  and  nearly  cylindrical  cone  cr, 
serves  as  a  guide  for  applying  the  grinder  to  the  short  obtuse 
cone  #,  which  is  completed  with  a  grinder  fitting  both  cones, 
and  finally  the  cone  a  is  separately  corrected  with  a  single  cone 
grinder. 

By  far  the  more  accurate  methods  of  grinding  the  external 
cone  are  however  the  employment  of  the  end  of  a  fixed  grinder, 
or  the  edge  of  a  revolving  lap  mounted  in  the  sliding  rest,  while 
the  work  revolves  in  the  lathe  exactly  in  the  manner  explained 
on  page  1237,  for  the  production  of  cylindrical  surfaces,  except 
that  the  sliding  rest  is  swung  round  to  the  suitable  angle  for  the 
side  of  the  cone.  One  of  these  methods  is  generally  resorted  to 
for  works  requiring  the  greatest  accuracy,  as  it  admits  of  the 
cone  being  corrected  with  considerable  exactness,  both  for  angle 
and  straightness  of  the  sides,  and  the  circular  section  being 
derived  directly  from  the  lathe,  the  adjustment  of  the  diameter 
is  the  principal  object  requiring  attention. 

The  method  of  a  fixed  grinder  may  also  be  resorted  to  for 
grinding  the  internal  cone,  when  the  works  admit  of  being 


GRINDERS    FOR    CONICAL    HOLES.  1254 


chucked  in  the  lathe,  and  the  opening  is  of  sufficient  size  for  the 
admission  of  a  rigid  grinder ;  but  conical  holes  are  seldom  so 
large  as  to  admit  of  a  revolving  lap,  and  extreme  accuracy  is 
less  frequently  required  in  the  preparation  of  the  internal  cone, 
as  the  very  minute  errors  incidental  to  the  ordinary  process  of 
grinding,  will  be  partially  corrected  by  the  final  grinding  together 
of  the  two  cones  to  ensure  contact. 

Internal  cones  are  generally  ground  upon  solid  grinders,  mostly 
formed  of  tin  cast  upon  an  iron  rod  and  turned  to  the  corre- 
sponding form.  The  best  works  are  completed  with  brass  grinders 
which  from  being  harder  retain  their  forms  longer  unimpaired 
and  therefore  leave  the  holes  more  accurate. 

For  short  conical  holes  in  small  objects  such  as  rings  or 
detached  collars,  the  grinder  is  mounted  in  the  lathe,  generally 
between  centers,  and  the  work  is  passed  over  the  rod  before  the 
screw  of  the  popit  head  is  adjusted,  but  sometimes  the  grinder 
is  made  as  a  chuck  to  screw  at  once  upon  the  lathe  mandrel ;  this 
arrangement  allows  of  the  work  being  more  readily  removed. 
In  either  case  the  work  is  applied  in  just  the  same  manner  as 
for  grinding  the  external  cone.  The  work  when  small  is  held  in 
the  fingers,  and  at  frequent  intervals  is  allowed  to  be  carried 
partly  round  by  the  grinder,  so  as  continually  to  change  its  posi- 
tion, to  compensate  for  any  irregularity  of  direction  in  holding 
the  work.  When  the  hole  is  large  and  the  friction  is  so  great 
that  the  object  cannot  be  held  steadily  in  the  hands,  it  is  fixed 
in  a  clamp  such  as  fig.  1112,  or  in  the  center  of  a  pulley  to  serve 
as  a  handle. 

Long  conical  holes,  such  as  axletree  boxes,  are  sometimes 
ground  upon  the  spring  grinder  fig.  1120,  which  may  be  viewed  as 

FIG.  1120. 


a  combination  of  figs.  1116  and  1117,  but  made  to  screw  directly 
upon  the  lathe  mandrel  after  the  manner  of  a  chuck,  and  closed 
by  two  or  three  binding  screws;  the  elasticity  of  the  spring 
suffices  for  keeping  the  halves  of  the  grinder  distended,  and  the 


1255          GRINDING    CONICAL    COLLARS    FOR   LATHE    MANDRELS. 


work  grasped  in  a  clamp  with  a  double-ended  lever  is  applied  in 
the  same  manner  as  small  objects,  the  workman  standing  in 
front  of  the  grinder,  the  binding  screws  of  which  are  gradually 
slackened  with  the  progress  of  the  work,  so  as  to  avoid  the  neces- 
sity for  employing  more  than  one  grinder. 

The  conical  collars  of  hardened  steel  generally  employed  for 
the  bearings  of  lathe  mandrels,  as  will  be  adverted  to  in  the  suc- 
ceeding volume>  are  required  to  be  made  not  only  as  accurately 
as  possible  to  the  same  angle  and  diameter  as  the  cone  that 
is  to  work  within  the  collar  itself,  but  the  axes  of  both  bear- 
ings should  also  be  strictly  in  a  line  with  each  other.  In  the 
mandrel  the  axes  of  the  two  cones  are  placed  straight,  almost 
without  the  possibility  of  error,  by  turning  both  cones  in  the 
lathe  from  the  same  centers,  but  a  less  direct  mode  is  from 
necessity  resorted  to  for  ensuring  the  straightness  of  the  axes  of 
the  two  bearings,  which  are  sometimes  both  made  as  detached 
rings,  or  collars  of  steel,  fitted  into  cylindrical  holes  in  the  lathe 
head  ;  at  other  times,  the  mandrel  works  in  a  collar  and  center 
screw.  The  parallelism  of  the  holes  for  the  reception  of  the 
bearings  is  obtained  by  boring  both  holes  at  the  one  fixing,  with 
the  cutter  bar  described  at  page  569,  Vol.  II.  The  collars  are 
turned  singly  in  the  lathe  to  the  required  cone,  but  a  little  smaller 
in  diameter  than  the  finished  size,  they  are  then  fixed  upon  a 
mandrel  revolving  truly  in  the  lathe,  and  the  exterior  turned  to 
fit  the  holes  in  the  lathe  head,  the  steel  collars  are  afterwards 
hardened  and  driven  in.  This  method  places  the  axis  of  the 
conical  collar  so  nearly  in  a  line  with  the  second  bearing,  that 
the  trifling  correction  necessary  for  position,  is  brought  within  the 
limits  of  the  grinding  necessary  for  fitting  the  mandrel  into 
the  collar,  and  which  is  effected  with  a  grinder  made  nearly 
as  a  copy  of  the  mandrel,  so  far  as  the  two  bearings  are  con- 
cerned, the  one  of  which  serves  as  a  guide  for  the  position  of 
the  grinder  while  the  other  bearing  is  being  ground. 

The  mandrels  of  small  lathes  are  usually  made  to  work  at  the 
back  end  in  a  conical  center,  and  at  the  front,  through  a  conical 
collar  the  smaller  diameter  of  which  is  outwards,  and  conse- 
quently in  correcting  the  collar  after  it  has  been  fixed  in  the 
lathe  head,  the  grinder  has  to  be  inserted  from  the  inside, 
between  the  two  bearings ;  the  form  of  grinder  usually  employe 
for  this  purpose  is  represented  in  fig.  1121.  A  center  sci 


GRINDING   CONICAL    COLLARS    FOR   LATHE    MANDRELS,          1256 


having  a  cylindrical  fitting  in  the  back  upright  of  the  lathe  head, 
is  used  for  keeping  the  grinder  straight,  and  the  square  end  of 
the  rod  upon  which  the  grinder  is  cast,  passes  through  the  conical 


FIG.  1121. 


]> 


)llar  and  is  received  in  the  square  hole  chuck  of  a  lathe,  by 
the  grinder  is  driven ;  while  the  end  traverse  for  advancing 
collar  lengthways  upon  the  grinder  is  given  by  the  back 
senter  screw,  which  is  supported  by  the  popit  head  of  the  lathe 
jmployed  for  driving  the  grinder.     The  center  screw  on  which 
the  grinder  revolves  is  screwed  into  a  clamp,  fixed  on  the  lathe 
lead  being  ground,  so  that  the  advance  of  this  screw  through  its 
imp  traverses  the  lathe  head  upon  the  grinder,  which  revolves 
one  position,  while  the  lathe  head  is  shifted  to  and  fro,  and 
iwisted  round   at   all  angles,  to   maintain  a  continual  change 
the  relative  positions  of  the  grinder  and  work. 
Sometimes  instead  of  driving  the   grinder   with  continuous 
lotion  by  the  lathe,  a  pulley  fixed  on  the  middle  of  the  rod  of 
10  grinder,  is  used  to  work  the  grinder  by  hand  as  usual ;  at 
>ther  times  a  cord  is  wound  around  the  pulley  and  led  to  a 
spring  fixed  overhead  like  a  pole  lathe,  so  as  to  revolve  the 
-inder  alternately  backwards  and  forwards. 
Large  lathe  mandrels  are  usually  made  to  work  through  two 
mical  collars  in  order  to  allow  of  wheels  being  fixed  on  the 
)k  end  of  the  mandrel.     The  two  conical  collars  are  mostly 
round  separately  in  the  first  instance,  the  same  as  in  correcting 
cylindrical  collars  of  traversing  mandrels.     The  grinder  is 

FIG.  1122. 


len  made  as  in  fig.  1122,  with  a  conical  grinder  of  tin  or  brass 
:ed  upon  an  iron  rod,  the  opposite  end  of  which  is  turned 
3ylindrically,  and  traverses  through  a  conical  plug  having  a  central 
cylindrical  hole  that  is  fitted  into  the  back  collar,  and  serves  as 
a  guide  for  traversing  the  grinder  in  a  straight  line,  while  the 


1257     THE    PRODUCTION    OF    SPHERICAL    SURFACES    BY  ABRASION. 

front  collar  is  being  ground  ;  the  back  collar  is  afterwards  ground 
in  the  same  manner,  a  plug  being  fitted  to  the  front  collar  as 
a  guide. 

The  principal  errors  having  been  removed  with  the  single  cone 
grinders,  the  collars  are  further  corrected  in  the  same  manner 
with  a  grinder  having  two  brass  cones,  made  exactly  as  a  coun- 
terpart of  the  mandrel,  and  supplied  with  flour  emery  and  water. 
Finally  the  mandrel  itself  is  ground  into  the  collars,  first  with 
very  fine  emery  and  oil,  and  lastly  with  oil  alone  for  the  final 
polish. 

When  the  works  are  so  large  as  not  to  be  perfectly  under 
control  in  the  horizontal  position,  or  that  the  weight  of  the 
grinder  would  be  liable  to  cause  the  lower  side  of  the  collars  to 
be  ground  in  excess,  the  lathe  head  is  placed  vertically,  and  a 
cord  attached  to  the  grinder  is  passed  over  a  pulley  above  and 
led  to  a  counterpoise,  to  sustain  the  principal  weight  of  the 
grinder.  By  this  arrangement  the  irregularities  of  fitting  in 
the  cones  can  be  more  readily  appreciated  by  the  sense  of  feel- 
ing, which  is  principally  depended  upon  for  the  condition  of  the 
work. 


SECT.   IV. THE   PRODUCTION    OF    SPHERICAL    SURFACES    BY    ABRASION. 

THE  grinding  and  polishing  of  spheres  in  hardened  steel,  glass, 
and  other  hard  substances,  after  the  method  invented  by  the  late 
Mr.  Henry  Guy,  (at  that  time  a  workman  in  the  employ  of 
Holtzapffel  &  Co.,)  is  perhaps  one  of  the  most  unexceptionable 
examples  of  the  production  of  form  by  abrasion,  as  the  principle 
being  almost  mathematically  correct,  the  true  spherical  form  is 
certain  to  be  produced  under  proper  management. 

The  mode  is  based  upon  the  section  of  a  perfect  sphere  being 
at  every  part  a  true  circle,  and  if  the  ball  be  previously  prepared 
nearly  of  the  spherical  shape,  and  placed  within  a  circular 
grinding  tool  or  ring  of  smaller  diameter,  so  as  to  bear  only  on  a 
narrow  circular  ring,  upon  putting  the  ball  in  rotation  equally  in 
every  direction,  the  most  prominent  points  of  the  ball  will  be 
successively  reduced,  until  the  section  at  all  points  is  made  truly 
circular,  when  the  perfect  sphere  will  result. 

The  method  of  fulfilling  these  conditions  ultimately  arrived  at 
by  Mr.  Guy  was  as  follows.  The  grinder  was  formed  of  a  bar 


GUY'S   METHOD    OF    GRINDING    SPHERES. 


1258 


of  iron  or  brass,  equal  in  thickness  to  about  one-third  the 
diameter  of  the  ball,  and  near  the  end  of  the  grinder  was  made 
a  conical  hole,  the  sides  of  which  formed  an  angle  of  about 
25  degrees,  and  sufficiently  large  to  allow  about  one-fourth  of 
the  diameter  of  the  ball  to  project  through  the  smaller  side. 
The  universal  rotation  of  the  ball  within  the  grinding  tool,  upon 
which  the  whole  method  depends,  will  be  explained  by  the 
diagram  fig.  1123  in  which  A  represents  a  large  circular  disk  sup- 


FIGS.  1123. 


1124. 


1126. 


posed  to  be  revolving  in  the  direction  of  the  arrows.  If  the  ball 
be  placed  within  the  grinder,  and  carried  round  in  contact  with 
the  face  of  the  revolving  disk,  on  the  dotted  line  or  thereabouts, 
the  arrows  will  in  every  case  represent  the  direction  of  the  rota- 
tion of  the  ball,  caused  by  the  revolution  of  the  disk.  At  1, 
the  ball  will  revolve  towards  the  handle,  at  2  perpendicularly 
upwards,  at  3,  horizontally  from  the  handle,  and  so  on,  in  fact 
in  every  position  the  axis  of  rotation  of  the  ball  will  be  the 
radius  of  the  large  disk  A,  and  as  the  ball  is  slowly  traversed 
around  the  disk,  the  axis  of  rotation  will  at  every  instant  be 
changing  in  regular  succession. 

Two  such  disks  are  employed  to  rotate  the  ball,  the  interval 
between  them  being  so  regulated  as  to  be  exactly  equal  to  the 
diameter  of  the  ball,  and  they  are  made  to  travel  at  equal  velo- 
cities in  opposite  directions.  The  disks  therefore  nip  the  ball 
tight,  and  by  their  simultaneous  action  on  opposite  sides  they 
cause  its  rotation,  notwithstanding  the  resistance  of  the  grinder. 


1259  GUY'S    METHOD    OP    GRINDING   SPHERES. 


The  two  disks  are  made  as  wooden  surface  chucks  about 
10  inches  diameter,  turned  quite  true  on  the  face,  and  fixed  on 
two  lathe  heads  that  are  mounted  face  to  face  upon  the  same 
frame  or  bearers,  so  as  to  bring  the  axes  of  both  lathe  heads  in 
exactly  the  same  line,  with  the  faces  of  the  disks  parallel  to  each 
other,  and  at  such  a  distance  asunder  as  will  suffice  to  press  the 
ball  sufficiently  firm  to  cause  its  rotation.  To  allow  of  the  ball 
being  firmly  held  with  moderate  pressure,  the  wooden  disks  are 
required  to  be  slightly  yielding,  so  as  to  permit  the  ball  to  be 
somewhat  embedded  in  the  surfaces  of  the  disks  to  give  a  better 
hold.  Boxwood  is  too  hard  for  this  purpose,  and  beech  wood 
answers  much  better  when  cut  transversely  out  of  large  blocks, 
so  that  the  end  grain  of  the  wood  constitutes  the  sides  of  the 
disks.  For  polishing  the  balls,  the  disks  are  covered  with  buff 
leather. 

The  edges  of  the  disks  are  turned  with  grooves  of  equal 
diameter  for  the  reception  of  a  catgut  band,  and  in  order  to 
ensure  the  tension  being  alike  upon  each,  it  is  better  to  employ 
only  one  band  leading  from  two  grooves  on  the  driving-wheel  to 
the  two  disks,  the  band  being  crossed  on  its  path  to  the  one 
disk  and  open  on  the  other,  so  as  to  give  them  equal  but  opposite 
revolutions.  The  more  rapidly  the  disks  revolve  the  quicker  the 
process  will  be  effected,  and  for  grinding  metal  balls  the  velocity 
should  not  be  less  than  about  400  revolutions  in  the  minute. 

Mr.  Guy  proposed  that  one  of  the  lathe  mandrels  employed 
should  have  the  power  of  sliding  endways  through  cylindrical 
bearings,  like  a  screw  mandrel  lathe,  in  order  that  the  disks 
might  be  kept  constantly  pressed  against  each  other  with 
uniform  force,  by  means  of  a  spring,  or  a  lever  and  weight ;  but 
upon  trial  this  was  not  found  to  answer,  as  the  balls  were  not 
held  sufficiently  firm,  and  it  is  better  to  effect  the  required 
adjustment  by  slackening  the  holding-down  bolt  of  one  of  the 
lathe  heads,  and  advancing  it  bodily  by  slight  blows  of  a 
hammer. 

The  grinder  shown  one-quarter  size  in  figs.  1125  and  1126  is 
made  about  15  inches  long,  the  shaft  is  of  iron,  and  small  rings 
of  brass  are  inserted  in  the  square  enlargement  at  the  end,  to 
constitute  the  conical  grinding  surface,  which  is  broached  01 
to  the  angle  of  about  25  degrees  with  the  broach  fig.  1124. 

The  cone  of  the  grinder  requires  to  be  frequently  restore* 


GUY'S  METHOD  OF  GRINDING  SPHERES.  1260 

during  use,  as  much  of  the  truth  of  the  result  depends  upon  the 
narrowness  of  the  surface  contact  of  the  grinder,  which  should  be 
able  to  adapt  itself  readily  to  the  curvature  of  the  ball,  notwith- 
standing that  both  the  ball  and  grinder  are  continually  changing 

curvature,  and  that  the  ball  grinds  a  narrow  spherical  seat  in 
le  grinder. 

For  a  sphere  of  about  one  inch  diameter,  the  bearing  surface 
should  never  exceed  about  one-sixteenth  of  an  inch  wide.  Indeed 
in  the  first  attempts  at  grinding  a  sphere  by  this  method,  the 
>rocess  failed  from  a  jointed  grinder  in  halves  being  employed, 

it  embraced  too  large  a  portion  of  the  sphere,  so  that  perfec- 
tion could  not  be  attained  until  the  bearing  surface  was  very 
inch  reduced.  " 

Balls  of  hardened  steel,  to  be  ground  truly  spherical  and  of 
definite  diameter,  are  turned  while  in  the  soft  state,  as  nearly  as 
>ossible  to  the  spherical  form  under  the  test  of  a  ring  gage,  and 
ire  left  slightly  larger  than  the  finished  size.  The  balls  are 
ifterwards  hardened  by  inclosing  them  in  sheet  iron  boxes  filled 
dth  parings  of  horses'  hoofs,  or  bone  dust,  and  luted  with  moist 
slay.  The  whole  are  then  heated  to  a  cherry  red,  either  in  an 
)pen  fire  or  closed  furnace,  on  removal  from  the  fire  the  lid  of 
le  box  is  knocked  off,  and  its  contents  thrown  bodily  into  cold 
rater ;  the  balls  are  not  afterwards  tempered. 

In  grinding  the  balls,  they  are  placed  singly  within  the  conical 
lole  of  the  grinder,  a  small  quantity  of  oil  and  emery  is  then 
mt  into  the  space  between  the  larger  side  of  the  cone  and  the 

ill,  and  the  disks  being  put  in  rapid  revolution,  the  ball  and 
cinder  are  slipped  in  between  them,  while  they  are  in  motion, 
'he  grinder  is  held  horizontally  by  the  handle,  and  pressed 
sideways  against  the  ball  to  keep  the  conical  grinding  surface 

mally  in  contact  with  the  ball,  which  is  at  the  same  time 
lowly  but  uniformly  traversed  by  the  grinder  around  the  disks, 
dthin  about  one  inch  of  their  edges,  as  of  course  the  further 

e  ball  is  kept  from  the  center  of  the  disks,  the  more  rapidly  it 

ll  be  rotated. 

After  a  few  revolutions  of  the  ball  around  the  disks,  the 
latter  become  slightly  indented  with  circular  grooves,  which 
serve  as  guides  for  the  path  in  which  the  ball  is  traversed. 
Care  is  required  to  keep  the  disks  pressing  against  the  ball 
sufficiently  tight  to  cause  its  rotation  within  the  grinder,  or 


1261  GUY'S    METHOD   OF  GRINDING    SPHERES. 


otherwise  from  the  surfaces  of  the  disks  becoming  charged  with 
emery  they  will  act  as  laps  and  grind  facets  upon,  the  ball. 

It  is  quite  necessary  that  the  ball  should  be  constantly 
traversed  around  the  disks  with  uniform  motion,  as  should  it  be 
permitted  to  linger  for  a  longer  time  at1  one  part  of  the  circle 
than  another,  the  ball  would  be  more  ground  at  that  part,  and 
become  oval.  The  necessary  supply  of  emery  and  oil  is  given 
without  removing  the  ball  from  between  the  disks,  by  keeping 
up  the  circular  motion  with  the  one  hand,  while  a  little  oil  is 
dropped  upon  the  ball  as  it  revolves,  and  the  emery  may  be 
sprinkled  upon  it  in  like  manner. 

The  grinding  is  continued  until  the  ball  is  made  truly  spherical, 
and  so  near  to  the  required  size  that  upon  trial  it  will  barely 
enter  the  ring  gage,  previously  prepared  of  the  exact  diameter. 
The  final  adjustment  for  size  is  given  in  the  polishing  process, 
which  is  effected  with  dry  crocus,  sometimes  applied  on  a  conical 
tool  of  boxwood  of  exactly  the  same  form  as  the  brass  grinder, 
the  revolving  disks  being  covered  with  leather  or  cloth  to  prevent 
the  ball  from  being  scratched.  But  where  great  accuracy  of 
size  is  required,  this  method  is  almost  too  active  for  the  final 
adjustment,  and  the  method  more  completely  under  control, 
is  to  polish  the  balls  by  rubbing  them  in  all  directions  with  the 
fingers,  within  a  conical  brass  tool  supplied  with  dry  crocus. 
This  removes  the  circular  marks  given  between  the  disks,  pro- 
duces a  good  lustre,  and  allows  of  the  adjustment  for  size  being 
effected  with  almost  any  required  degree  of  exactness. 

Spheres  in  glass,  agate  or  other  hard  substances  that  do  not 
admit  of  being  turned  with  cutting  tools,  are  prepared  as  nearly 
as  admissible  of  the  spherical  form  by  grinding  them  by  hand 
after  the  method  of  the  lapidary.  The  balls  are  completed  by 
grinding  them  between  the  revolving  disks,  with  a  brass  or  iron 
grinder  just  the  same  as  the  hardened  steel  balls,  except  that 
water  is  employed  with  the  emery  instead  of  oil,  partly  with  the 
view  of  reducing  the  heat  occasioned  by  the  friction,  which  in 
the  case  of  grinding  glass  spheres  is  liable  to  cause  them  to 
become  cracked,  and  therefore  in  grinding  glass  balls  the  velocity 
of  the  disks  should  be  only  moderate,  and  water  should  be  sup- 
plied in  sufficient  quantity  to  keep  the  balls  tolerably  cool. 

The  glass  balls  are  lastly  polished  with  putty  powder,  applied 
on  a  wooden  polishing  tool,  the  conical  surface  of  which  is 


SPHERICAL    GRINDING    TOOLS    FOR    LENSES.  1262 


covered  with  wash  leather,  by  passing  the  latter  through  the 
hole,  and  securing  it  around  the  margins  with  a  few  tacks. 

The  method  of  grinding  marbles  for  children  is  described  in 
the  catalogue  of  grinding  processes  page  1078. 


The  spherical  surfaces  of  lenses,  are  produced  by  grinding 
them  in  counterpart  tools,  or  disks  of  metal,  prepared  to  the 
same  curvatures  as  required  in  the  lenses,  and  employed  as  the 
medium  for  the  application  of  the  grinding  and  polishing 
powders.  The  tools  are  made  in  pairs,  concave  and  convex, 
and  are  first  employed  mutually  to  correct  each  other's  errors ; 
as  the  accuracy  of  the  surfaces  of  the  lenses  is  principally 
dependent  on  the  tool  upon  which  they  are  ground,  being  accu- 
rately formed  to  the  counterpart  figure. 

For  the  formation  of  the  grinding  tools,  a  concave  and  a 
convex  template  are  first  made  to  the  radius  of  the  curvature 
of  the  required  lens.  The  templates  of  large  radius,  are  some- 
times cut  out  of  crown  glass  by  cementing  it  upon  a  bench,  and 
mounting  a  glazier's  diamond  upon  the  end  of  a  light  radius 
bar,  sometimes  only  a  rod  of  wood,  with  a  brad  awl  stuck 
through  the  rod  into  the  bench,  the  distance  from  the  diamond 
to  the  awl  being  the  radius  of  the  curve.  The  glass  having 
been  cut  with  the  diamond,  is  separated,  the  one  cut  forming 
the  concave  and  convex  edges,  which  are  afterwards  ground 
together  with  a  little  emery  and  water,  for  this  purpose  the 
templates  are  laid  upon  the  bench  and  rubbed  edge  to  edge  ; 
one  of  the  pieces  is  occasionally  turned  end  for  end  to  verify  the 
curves.  See  Tech.  Repos.  1822  page  365. 

More  generally  however  templates  of  large  and  medium 
radii  are  made  out  of  sheet  brass,  the  templates  of  long  radii 
are  cut  with  a  strong  radius  bar  and  cutter,  and  those  of  only  a 
few  inches  radii  are  cut  in  the  turning  lathe.  The  brass  concave 
and  convex  gages  are  cut  at  separate  operations,  as  it  is  neces- 
sary to  adjust  the  radius  to  compensate  for  the  thickness  of  the 
cutter,  and  the  brass  templates  are  not  usually  corrected  by 
grinding,  as  practically  it  is  found  more  convenient  to  fit  the 
tools  themselves  together. 

The  templates  having  been  made  of  the  required  radius,  are 
used  for  the  preparation  of  the  grinding  and  polishing  tools, 


1263  SPHERICAL    GRINDING    TOOLS    FOR    LENSES. 


which  for  convex  lenses  consist  of  a  concave  rough  grinding  tool 
of  cast  iron,  called  a  shell,  shown  in  section  in  fig.  1 1 27,  the 
wooden  pattern  of  which  is  turned  to  the  curve  of  the  template, 
and  the  shell  is  left  from  the  casting ;  a  similar  shell,  turned  to 
a  radius  of  about  three-eighths  of  an  inch  larger  than  the  tem- 
plate, serves  as  the  foundation  of  the  polisher,  the  preparation 
of  which  is  described  in  page  1267.  For  common  glasses,  that 
are  ground  several  together,  a  convex  tool  of  cast  iron,  called  a 
runner,  of  about  half  an  inch  less  radius  than  the  templates,  is 
also  required,  as  the  basis  upon  which  the  lenses  are  cemented, 
as  shown  in  fig.  1129. 

The  most  important  part  of  the  apparatus  is  however  a  pair 
of  brass  tools,  one  concave,  and  the  other  convex,  made  exactly 
to  the  curvature  of  the  templates,  and  to  fit  each  other  as 
accurately  as  possible.  The  concave  tool  is  used  as  the  grinder 
for  correcting  the  curvature  of  the  lenses,  after  they  have  been 
roughly  figured  in  the  concave  shell.  And  the  convex  tool  is 
employed  for  producing  and  maintaining  the  true  form  of  the 
concave  grinding  tool  itself,  and  also  that  of  the  polisher.  The 
pair  of  brass  tools  are  represented  in  section  in  fig,  1128. 


1129. 


The  backs  of  the  tools  are  provided  with  a  screw  exactly  the 
same  as  an  ordinary  chuck,  by  which  they  may  be  fitted  on  the 
lathe  mandrel,  to  be  turned  to  the  curvature  of  the  templates, 
and  by  which  they  may  also  be  attached  to  the  top  of  a  perpen- 
dicular post  or  pedestal,  about  three  feet  high,  strongly  fixed  to 
the  floor  of  the  workshop,  and  carrying  at  the  top  an  iron  block 
having  a  vertical  screw,  exactly  a  copy  of  that  upon  the  lathe 
mandrel. 

The  pair  of  brass  tools  having  been  turned  to  the  curvature 
of  the  templates,  they  are  next  corrected  by  grinding  them 
together ;  for  this  purpose  the  convex  tool  is  fixed  by  its  screw 


SPHERICAL    GRINDING    TOOLS    FOR    LENSES.  1264 


upon  the  perpendicular  post,  and  the  screw  at  the  back  of  the 
concave  tool  is  fitted  with  a  wooden  handle  of  a  bulbous  form, 
and  sufficiently  large  to*  be  grasped  by  the  two  hands. 

The  concave  tool  is  placed  upon  the  convex,  and  the  two  are 
rubbed  together,  first  without  any  grinding  powder,  to  denote 
by  the  parts  brightened  where  they  bear  the  hardest,  as  the 
manner  in  which  they  are  ground  together  depends  in  some 
respects  upon  the  nature  of  the  general  error  to  be  corrected. 
Should  the  tools  not  fit  each  other  tolerably  well,  the  principal 
errors  are  reduced  by  turning  until  they  agree  nearly  uniformly 
throughout  their  surfaces  and  touch  about  equally  at  the  center 
and  margins  of  the  tools,  the  minute  errors  are  then  removed  by 
grinding,  which  is  usually  done  with  emery  and  water,  but  as 
previously  explained  at  page  1229,  with  respect  to  the  grinding 
of  flat  tools  for  the  parallel  disks  for  sextants,  Mr.  Andrew  Ross 
.  found  that  greater  accuracy  was  obtained  by  using  the  emery 
dry.  But  whether  wet  or  dry  grinding  be  resorted  to  for  the 
correction  of  the  tools,  the  emery  should  be  as  uniformly  distri- 
buted as  possible,  by  rubbing  it  level  with  a  piece  of  glass  of 
corresponding  curvature,  and  any  excess  of  emery  around  the 
margin  of  the  tool  is  wiped  off,  as  there  should  be  rather  a 
deficiency  than  otherwise  near  the  edges. 

The  concave  tool  is  now  placed  upon  the  convex,  and  worked 
with  a  circular  swinging  stroke,  somewhat  as  in  rubbing  the  hand 
over  the  upper  surface  of  a  large  ball,  but  instead  of  the  motion 
being  given  by  the  arms^alone,  the  body  should  at  the  same  time 
be  swung  round,  also  in  a  circular  path,  so  as  to  give  a  free 
bold  stroke  to  the  tool,  but  continually  varied  a  little  in  extent 
and  direction.  Between  every  few  strokes  the  operator  moves 
a  little  way  around  the  post,  so  as  to  continually  change  the 
position  in  which  he  stands,  and  gradually  travel  round  the  post. 
In  every  position  he  twists  the  upper  tool  partly  round  in  his 
hands,  so  as  by  the  combination  of  the  various  movements  to 
bring  the  two  surfaces  in  contact  in  every  possible  position,  and 
rub  them  upon  each  other  at  all  angles. 

If  either  at  the  commencement,  or  during  the  process  of 
grinding,  the  tools  should  be  found  to  bear  the  hardest  near 
the  middle  of  the  curve,  the  strokes  are  made  short,  and  occa- 
sionally varied  from  the  circular  path  to  that  of  a  narrow 
ellipsis,  and  the  pressure  is  principally  applied  vertically;  but 


1265  PREPARATION  OF  GLASS  DISKS  FOR  LENSES. 


if  the  tools  bear  the  hardest  near  the  edges  of  the  curve,  long 
bold  circular  strokes  are  taken,  with  the  pressure  principally 
sideways.  In  extreme  cases  the  concave  tool  is  fixed  on  the 
post,  and  the  convex  tool  held  in  the  hands  is  worked  within  it, 
with  a  swinging  stroke,  so  as  to  grind  the  tools  at  the  sides 
onlv ;  but  as  a  general  rule,  the  convex  tool  is  fixed  on  the  post 
in  all  cases,  as  the  spherical  figure  may  be  more  conveniently 
ground  in  this  position. 

The  determining  of  the  length  and  direction  of  the  stroke, 
and  also  whether  it  should  be  circular  or  elliptical,  are  points 
that  must  be  left  principally  to  the  judgment  of  the  operator, 
guided  in  great  measure  by  the  sense  of  feeling ;  but,  speaking 
generally,  it  may  be  said  that  large  circular  strokes  increase  the 
radius  of  curvature  of  the  concave  tool,  from  the  margins  being 
more  acted  upon  than  the  center  ;  while  short  elliptical  strokes 
have  the  contrary  effect.  The  curvature  of  the  convex  tool 
undergoes  much  less  change,  from  the  two  modes  of  working, 
and  therefore  when  it  is  desired  to  alter  the  curvature,  the 
convex  tool  is  first  employed  to  alter  the  concave  tool,  and  the 
convex  is  then  fitted  to  it.  The  principal  object  aimed  at  is  to 
make  the  tools  of  the  true  spherical  figure,  and  to  fit  each  other 
exactly,  a  small  departure  from  the  intended  'radius  being  in 
general  less  important  than  the  correctness  of  the  figure. 

The  glass  for  the  lenses  having  been  selected  of  suitable 
quality  they  are  brought  to  the  circular  form  with  flat  pliers 
called  shanks,  the  jaws  of  which  are  made  of  soft  iron  that  they 
may  the  more  readily  embed  themselves  upon  the  glass  and  take 
a  firm  hold  ;  if  the  jaws  were  made  of  hardened  steel  they  would 
be  liable  to  slip.  The  pressure  of  the  pliers  applied  near  the 
edges  of  the  glass  causes  it  to  crumble  away  in  small  fragments, 
and  the  process  which  is  called  shanking  or  nibbling  is  continued 
until  the  glasses  are  made  circular,  and  of  a  little  larger  diameter 
than  the  finished  size  of  the  lenses. 

They  are  next  coated  on  one  side  with  a  layer  of  cement 
about  half  an  inch  thick  to  form  a  handle,  by  pouring  the  melted 
cement  from  a  ladle  upon  the  glass  in  small  quantities,  as  much 
as  will  lay  on  the  glass  without  running  off,  and  as  soon  as  it  is  set, 
a  further  supply  is  added  until  the  cement  forms  a  hemispherical 
mass,  sufficiently  thick  to  be  readily  grasped  in  the  fingers. 

The  cement  is  made  by  mixing  sifted  wood  ashes  with  melt< 


GRINDING   LENSES.  1266 


pitch,  the  essential  oil  of  which  is  absorbed  by  the  wood  ashes, 
and  the  adhesiveness  of  the  pitch  is  thereby  reduced.  The 
proportions  are  somewhat  dependent  on  the  temperature  of  the 
weather,  and  the  quality  of  the  pitch  ;  but  generally  about  4lbs. 
of  wood  ashes  to  141bs.  of  pitch  are  employed,  and  the  cement  if 
too  hard  and  brittle  is  softened  with  hog^s  lard,  or  tallow. 

The  glasses  are  in  all  cases  rough  ground  separately  within  the 
shell,  fig.  1127,  either  with  river  sand  and  water,  or  coarse  emery 
and  water,  until  the  surfaces  are  brought  nearly  to  the  curve  of 
the  shell.  The  glasses  are  rubbed  with  large  circular  strokes, 
and  the  shell  is  usually  placed  within  a  shallow  tray,  to  catch 
the  loose  sand  or  emery  thrown  off  in  the  grinding.  The  second 
side  is  rough  ground  in  the  same  manner,  the  glass  being  warmed 
for  the  removal  of  the  cement  handle,  which  is  transferred  to 
the  other  side.  The  parallelism  of  the  two  sides  is  obtained  by 
observing  that  the  edge  of  the  glass  is  left  of  equal  thickness  all 
round. 

So  far  the  lenses  whether  large  or  small,  and  of  the  best  or 
common  quality,  are  treated  alike,  but  for  grinding  the  glasses 
to  the  correct  form  in  the  brass  tool,  and  also  for  polishing,  they 
are  operated  upon  either  singly  or  several  together,  according  to 
the  size  and  degree  of  accuracy  required  in  the  lenses.  The 
best  lenses  for  the  object  glasses  of  telescopes  being  ground  and 
polished  singly,  while  on  the  other  hand  as  many  as  four  dozen 
of  common  spectacle  glasses  are  sometimes  cemented  upon  a 
runner  and  ground  and  polished  at  the  same  time.  When 
several  lenses  are  to  be  ground  and  polished  together,  the 
number  must  be  such  as  admits  of  being  arranged  symmetrically 
around  a  central  lens,  as  7,  13  or  21,  at  other  times  a  group  of 
four  forms  the  nucleus,  and  the  numbers  run  4,  14,  30.  Lenses 
of  medium  quality  and  size  are  however  generally  ground  true 
and  polished  seven  at  a  time. 

The  cement  at  the  back  of  the  lenses^  is  first  flattened  with  a 
heated  iron,  and  the  seven  lenses  are  then  arranged  with  the 
cemented  sides  upwards  in  the  concave  brass  tool,  one  lens 
being  placed  in  the  center,  and  the  other  six  at  equal  distances 
around  it,  very  near  together  but  without  touching.  The  cast 
iron  runner  is  then  heated  just  sufficiently  to  melt  the  cement, 
and  carefully  placed  upon  the  cemented  backs  of  the  lenses. 
As  soon  as  the  cement  is  sufficiently  softened  to  adhere  firmly 

VOL.  Til.  R 


1267  PREPARATION    OF    POLISHING    TOOLS    FOR    LENSES. 

to  the  runner,  the  latter  is  cooled  with  a  wet  sponge,  as  the 
cement  must  be  only  so  far  fused  as  to  fill  up  the  spaces  nearly, 
but  not  quite,  level  with  the  surface  of  the  lenses. 

The  block  of  lenses,  shown  in  fig.  1129,  is  now  mounted  upon 
the  post,  and  ground  with  the  concave  brass  tool,  fig.  1128,  in 
exactly  the  same  manner  as  explained  for  correcting  the  forms 
of  the  tools  themselves.  About  six  sizes  of  washed  emery 
progressively  finer  are  employed  for  grinding  the  lenses  to  the 
true  figure,  or  as  it  is  called  trueing  the  lens,  the  last  size  of 
emery  being  the  fine  powder  collected  after  one  hour's  sub- 
sidence as  explained  at  page  1055-6,  and  which  leaves  so  smooth 
a  surface,  that  when  the  lens  is  held  between  the  eye  and  the 
light,  it  shows  a  semi-polish. 

Of  course  the  grinding  is  continued  with  every  size  of  emery 
until  all  the  marks  made  with  the  previous  size  are  removed, 
and  between  every  change,  the  brass  tool,  hands  and  block  of 
lenses,  are  thoroughly  washed,  and  wiped  first  with  damp  and 
afterwards  with  dry  cloths,  to  remove  every  particle  of  the 
previous  emery,  which  without  the  greatest  possible  care  would 
be  especially  liable  to  lodge  in  the  spaces  between  the  lenses, 
and  might  near  the  conclusion  of  the  work  become  detached, 
and  make  a  scratch  that  would  render  it  necessary  to  recom- 
mence the  grinding. 

The  lenses  have  next  to  be  polished,  for  ordinary  lenses  of 
medium  gize,  the  polisher  is  made  by  warming  a  cast  iron  shell, 
and  coating  it  uniformly  about  one  quarter  of  an  inch  thick  with 
melted  cement.  A  piece  of  thick  woollen  cloth,  such  as  was 
formerly  used  for  watchmen's  coats,  is  cut  to  the"  size  of  the 
polisher,  and  unless  the  cloth  is  old  and  the  nap  worn  off,  it  is 
seared  with  a  heated  iron.  The  cloth  is  placed  on  the  cement 
in  the  polisher,  and  pressed  into  form  by  working  the  brass 
convex  tool  within  it ;  the  pores  of  the  cloth  are  then  filled  up 
with  putty  powder  prepared  as  explained  on  page  1088.  The 
putty  powder  is  mostly  sifted  through  lawn,  and  enclosed  in  a 
box  having  a  lid  perforated  with  small  holes.  The  putty  powder 
is  shook  uniformly  over  the  cloth,  and  moistened  by  sprinkling 
a  few  drops  of  water  over  it ;  the  powder  is  then  worked  into 
the  pores  of  the  cloth  with  the  brass  convex  tool,  additional 
powder  being  applied  until  the  surface  is  made  quite  level,  and 
it  is  worked  quite  smooth  with  the  tool ;  from  two  to  three  hours 


tn 

ca 

th 


POLISHING   LENSES.  1268 

being  generally  required  for  making  up  a  polisher  of  8  or  9 
inches  diameter.  Kerseymere  is  sometimes  used  for  small 
lenses  instead  of  the  thick  cloth,  principally  because  the  face 
of  the  cloth  being  finer  it  is  sooner  filled  up  with  the  putty 
powder. 

The  polisher  when  completed  is  placed  upon  the  block  of 
lenses,  still  fixed  on  the  post,  and  worked  with  wide  and  narrow 
elliptical  strokes,  the  operator  continually  walking  around  the 
post  the  same  as  for  grinding.  The  point  requiring  the  prin- 
cipal attention  is  the  degree  of  moisture  of  the  putty  powder, 
which  should  be  only  moderate ;  if  too  wet  the  putty  is  apt  to 
run  loose  upon  the  polisher,  which  produces  a  curdled  surface  so 
difficult  to  remove  that  when  once  produced  it  is  generally 
necessary  to  return  to  the  fine  grinding.  If  upon  the  other 
hand  the  polisher  is  allowed  to  become  too  dry,  it  is  indicated 
by  the  edges  of  the  lenses  cutting  up  the  surface  of  the  putty 
powder,  which  then  works  with  an  unpleasant  scratching  action 
that  will  be  immediately  detected. 

The  proper  degree  of  moisture  of  the  putty  powder,  is  indi- 
ited  by  its  being  in  a  rather  stiff  saponaceous  state,  and  during 
the  principal  portion  of  the  polishing,  the  surface  should  present 
a  partially  glazed  appearance.  When  the  surface  becomes 
almost  entirely  glazed,  a  little  more  water  is  sprinkled  on  it ; 
but  towards  the  conclusion  of  the  polishing  less  moisture  is  used, 
and  the  polisher  is  allowed  to  become  as  nearly  dry  as  is  con- 
sistent with  safety,  the  glazed  appearance  then  covers  almost 
the  whole  surface. 

During  the  polishing  the  pressure  should  be  very  moderate, 
the  lenses  will  partially  sink  into  the  surface  of  the  polishing 
1,  and  become  rounded  at  those  parts  of  the  edges  which  are 
unsupported  by  the  neighbouring  lenses.  This  evil  may  be 
partially  remedied  by  cutting  off  a  portion  of  the  circumference 
in  the  manner  alluded  to  on  page  1229.  But  in  order  to  avoid 
the  rounding  as  much  as  possible,  the  more  accurate  the  lenses 
are  required  to  be,  the  less  the  pressure  that  is  employed  in 
rubbing  them  on  the  cloth  polisher. 

The  edges  of  the  lenses  are  finally  ground  circular,  and  of 
course  the  axes  of  the  lenses  should  when  put  into  the  tubes  of 
the  instruments,  be  perfectly  parallel  with  the  axis  of  the  tubes; 
to  attain  this  they  are  cemented  upon  a  chuck  in  the  lathe,  and 

B2 


the 

I 


1269  GRINDING    COMMON   LENSES    BY    MACHINERY. 

before  the  cement  has  set  the  lathe  is  put  in  revolution,  and  the 
reflection  of  any  fixed  object  such  as  a  candle,  or  a  bar  of  the 
window,  is  watched,  and  the  lens  is  adjusted  until  the  image 
appears  strictly  stationary,  notwithstanding  the  revolution  of 
the  lens,  and  which  shows  the  axis  of  the  lens  and  that  of  the 
mandrel  of  the  lathe  to  be  in  agreement;  The  edge  is  then 
ground  circular  with  a  piece  of  brass  supplied  with  emery  and 
water.  The  piece  of  brass  being  placed  beneath  the  lens,  and 
gradually  elevated  by  a  screw  tapped  through  one  end,  while  the 
other  rests  upon  any  convenient  prop  on  the  lathe  bearers. 

Concave  lenses  are  ground  and  polished  in  the  same  manner 
as  convex  lenses,  except  that  they  are  fixed  in  the  concave  tools 
and  ground  upon  the  convex,  which  as  before  mentioned  is 
always  the  lower  tool,  when  several  glasses  are  operated  upon 
together. 

In  Mr.  C.  Varley's  lathe  for  grinding  and  polishing  lenses  and 
specula,*  instead  of  the  lower  tools  being  mounted  upon  a  fixed 
post,  they  are  mounted  upon  a  revolving  axis,  placed  vertically. 
This  considerably  expedites  the  process,  which  is  conducted  in 
exactly  the  same  manner  in  all  other  respects,  but  the  necessity 
for  walking  around  the  lower  tool  is  removed.  It  is  however 
generally  considered  that  the  method  of  grinding  lenses  of  medium 
and  large  sizes,  with  a  tool  mounted  on  a  rapidly  revolving  axis, 
is  less  accurate  than  when  the  tool  is  fixed ;  and  that  when 
circular  motion  is  given  to  the  tool,  it  should  be  so  slow  as 
only  to  give  change  of  position,  leaving  the  abrasion  to  be 
effected  principally  by  the  elliptical  or  circular  strokes. 

In  manufactories  where  large  quantities  of  common  lenses  are 
ground  and  polished,  these  operations  are  principally  effected  by 
machinery.  The  block  of  lenses  is  mounted  upon  a  slowly 
revolving  axis,  placed  vertically,  and  the  upper  tool  has  an 
eccentric  motion  given  to  it,  by  means-of  a  small  crank  fixed  on 
the  lower  end  of  a  second  vertical  axis,  that  is  placed  a  little  on 
one  side  of  the  central  line  of  the  lower  axis.  A  pin,  fixed  in 
the  center  of  the  back  of  the  upper  grinding  tool,  enters  a  socket 
in  the  crank,  and  the  revolution  of  the  latter  causes  the  upper 
tool  to  describe  small  circles,  which,  combined  with  the  slow 
revolution  of  the  block  of  lenses,  causes  every  point  of  the  grinder 

*  Described  in  a  communication  to  the  Society  of  Arts.  See  Trans.,  Vol.  XL IX., 
page  91. 


GRINDING    BEST    LENSES    FOR    OBJECT    GLASSES.  1270 

to  describe  epicycloids  upon  the  surface  of  the  lenses,  much  the 
same  as  in  the  circular  strokes  employed  in  grinding  lenses  by 
hand.  The  radius  of  the  crank  admits  of  adjustment  to  give 
various  degrees  of  eccentricity  to  the  upper  tool,  and  the  pressure 
is  regulated  either  by  a  spring,  or  by  adjusting  the  weight  of  the 
grinder. 

As  previously  mentioned,  the  best  lenses  for  object  glasses  of 
telescopes  are  ground  and  polished  singly  by  hand  ;  in  this  case 
the  lens  whether  concave  or  convex  is  kept  in  the  hand,  and  the 
grinding  tool  is  fixed.  The  glass  if  small  is  held  by  a  cement 
handle,  and  if  large  is  cemented  to  a  metal  handle,  as  wood  is 
liable  to  swell  with  the  moisture. 

The  grinding  is  performed  in  exactly  the  same  manner  as 
when  several  lenses  are  ground  together,  but  greater  care  is 
taken  with  every  successive  step,  and  these  lenses  are  in  general 
polished  upon  a  piece  of  thick  silk,  the  kind  known  as  lutestring 
being  preferred. 

The  silk  cut  to  the  width  of  about  seven  eighths  the  diameter 
of  the  lens,  is  stretched  across  the  middle  of  the  brass  tool,  and  the 
lens  is  rubbed  backwards  and  forwards  in  straight  lines  along 
the  silk,  and  instead  of  the  operator  walking  around  the  post, 
'  the  lens  is  continually  twisted  round  in  the  Jiand,  and  at  the 
same  time  traversed  gradually  sideways  until  the  center  of  the 
lens  is  brought  to  the  edge  of  the  silk,  when  the  direction  of  the 
traverse  is  reversed.  The  single  thickness  of  silk  stretched 
across  the  tool  assumes  the  form  more  correctly  than  the  cloth 
polisher,  and  the  lens  is  traversed  partly  off  the  silk  in  order 
that  the  center  may  be  acted  upon  equally  with  the  margin. 

The  putty  powder  and  water  with  which  the  silk  polisher  is 
supplied,  are  kept  ready  mixed  in  a  corked  bottle  to  avoid  the 
contamination  of  dust,  and  at  the  time  of  application  the  bottle 
is  shaken  up,  and  its  contents  allowed  to  subside  for  a  few 
seconds,  a  small  quantity  of  the  water  is  then  taken  put  with  a 
clean  stick  and  thrown  upon  the  polisher,  and  thus  only  the 
suspended  portions  of  the  putty  powder  are  used.  The  most 
carefully  finished  lenses  are  polished  on  a  pitch  tool  prepared  in 
the  same  manner  as  for  polishing  specula. 

It  has  been  stated  at  page  1265,  that  with  ordinary  lenses 
accuracy  of  spherical  form  is  of  much  greater  importance  than 
the  radius  of  curvature,  but  in  making  the  object  glasses  of 


1271  ROSS*  SPHEROMETER. 


! 


achromatic  telescopes  it  is  requisite  to  be  enabled  to  measure 
accurately  the  radii  of  curvature  of  the  lenses,  which  are  first 
tried  experimentally,  and  afterwards  made  as  nearly  as  possible 
to  the  radii  obtained  by  calculation,  in  order  to  correct  the 
chromatic  and  spherical  aberration. 

In  1841  Mr.  Andrew  Ross,  (from  whose  practice  most  of  the 
foregoing  particulars  on  grinding  and  polishing  lenses  have  been 
derived,)  received  the  silver  medal  from  the  Society  of  Arts  for 
his  instrument,  called  a  spherometer,  for  measuring  the  curvature 
of  the  grinding  tools.  The  instrument  is  shown  in  fig.  1130,  and 
the  following  description  by  Mr.  Ross  is  extracted  from  Vol.  53 
of  the  Transactions  of  the  Society  : — 

"  During  a  series  of  experiments  instituted  many  years  since 
by  Professor  Barlow  for  verifying  his  methods  of  computing  the 
curvatures  of  an  achromatic  object  glass,  in  which  I  was  practi- 
cally engaged,  it  became  necessary  to  ascertain  with  consider- 
able accuracy  the  radii  of  curvature  of  the  tools  on  which  the 
lenses  were  ground.  The  method  then  adopted  was  that  of 
grinding  in  the  tool  the  edge  of  a  plate  of  glass,  till  the  edge 
accurately  fitted  the  tool,  and  formed  what  is  called  a  template. 
This  was  laid  upon  a  board  in  which  two  pins  were  inserted, 
and  the  template,  guided  by  the  pins,  was  made  to  describe  an 
arc  of  great  extent.  The  chord  and  versed  sine  of  this  large 
arc  being  carefully  drawn  and  measured  afforded  data  for  calcu- 

I  c\2 

lating  the  radius,  by  the  well-known  formula  2  R  =  ilL.-f-  v, 

where  R  is  the  radius,  c  the  chord,  and  v,  the  versed  sine. 
This,  though  obviously  not  a  very  precise  method,  was  suffi- 
ciently correct  for  verifying  the  theoretical  deductions,  and  it 
was  as  accurate  as  the  processes  then  employed  in  working  the 
glasses  for  telescopes." 

4  With  the  view  of  improving  these  processes,  and  rendering 
their  results  more  certain,  I  have,  for  more  than  two  years, 
been  carrying  on  a  course  of  experiments  to  discover  the  causes 
of  the  discrepancies  which  were  known  to  exist  between  theory 
and  practice  in  this  branch  of  optics.  Every  improvement  in 
the  processes  rendered  it  indispensable  to  determine  more  cor- 
rectly slight  variations  in  the  radii  of  curvature,  to  accomplish 
which  I  was  led  to  invent  the  instrument  which  I  now  offer  to 
the  notice  of  the  Society. 


ROSS     SPHEROMETER. 


1272 


"  Its  principle  and  general  features  are  explained  in  the 
accompanying  sketch,  where  T,  T,  represents  a  portion  of  the  con- 
vex tool  to  be  measured  ;  and  as  the  tools  are  of  necessity  made 


FIG.  1130. 


pairs  we  require  to  measure  only  one  of  each.  A  short 
cylinder  C,  C,  nearly  closed  at  one  end  has  its  edges  very 
accurately  turned  and  ground  to  a  portion  of  a  circle  whose  radius 
is  known.  In  the  cylinder  is  attached  a  carefully  made  square 
socket  S,  S,  in  which  fits  and  moves  the  square  index  bar  I,  I,  the 
extremities  of  which  are  finished  with  hard  steel  cones.  Upon 
these  conical  terminations  as  centers  the  circular  edge  of  the 
cylinder  C,  C,  is  ultimately  turned  and  ground,  so  that  all  errors 
of  workmanship  in  fitting  and  fixing  the  socket  to  the  cylinder 
are  completely  obviated.  The  index  bar  I,  I,  is  divided  on  one 
face  to  -Vth  of  an  inch,  and  a  vernier  V,  is  secured  to  the  socket 
by  which  it  may  be  read  to  -oVo-th  of  an  inch,  or,  by  estimation, 

to  2-oVo-th- 

"  If  the  edge  of  the  cylinder  had  been  made  square  instead  of 
circular,  then  the  clear  diameter  of  the  cylinder  would  have  been 
in  all  cases  the  value  of  the  chord  ;  but  the  difficulty  of  preserv- 
ing a  square  angular  edge  perfectly  true,  and  the  different  manner 
in  which  such  a  form  would  lie  on  spheres  of  small  and  large 
radii,  induced  me  to  adopt  the  circular  edge,  by  which  of  course 
the  value  of  the  measured  chord  varies  with  every  change  of 
curvature  in  the  tool."  To  obtain  the  value  of  the  radius  with- 
out determining  the  value  of  the  varying  chord  Mr.  A.  Ross 

devised  the  formula  R  =  v 


1273  GRINDING    LENSES    FOil    MICROSCOPES. 

a  =  The  known  semidiameter,  or  half  the  distance  between 
the  centers  of  the  small  circles  which  form  the  edge  (which 
is  determined  by  gently  rubbing  the  cylinder  on  a  perfectly 
flat  surface  and  measuring  the  diameter  of  the  ring  thus 
marked  on  the  circular  edge). 

v  =  The  apparent  versed  sine  as  indicated  by  the  vernier. 

r  =  The  known  radius  of  the  edge  of  the  spherometer. 

R  =  The  radius  of  the  tool  sought. 


Diminutive  microscopic  lenses,  whose  diameter  is  sometimes 
as  small  as  from  one  quarter,  to  one  twentieth  of  an  inch,  are 
also  ground  and  polished  singly,  as  the  radius  of  curvature  is  in 
general  too  small  to  allow  of  several  being  grouped  together. 
The  templates  are  made  as  small  disks  of  steel,  with  slender 
stems  turned  in  the  lathe  ;  for  lenses,  the  radii  of  whose  curva- 
ture are  5,  10  or  20  hundredths  of  an  inch  the  diameters  of 
the  disks  are  10,  20  or  40  hundredths.  They  are  made  with 
square  edges  and  when  hardened  are  applied  diametrically  as 
the  finishing  tools  for  turning  the  small  metal  cups  or  concave 
grinding  tools.  For  measuring  the  diameters  of  the  disks  they 
are  applied  either  in  the  sector  gage,  or  one  of  the  sliding  gages 
often  used  for  measuring  the  diameter  of  wire,  and  graduated 
decimally  for  reading  the  width  of  the  opening  to  the  hundredth 
or  thousandth  of  an  inch. 

The  cups  when  turned  are  charged  with  emery,  and  put  in 
rapid  revolution  in  the  lathe,  which  for  these  minute  lenses  is 
in  general  very  small,  and  worked  with  the  drill  bow.  The 
lens  is  cemented  with  shell-lac  upon  a  small  wooden  stick,  and 
held  against  the  grinding  tool  with  a  continual  change  of  angle, 
the  end  of  the  stick  being  moved  in  the  arc  of  a  circle,  while  it 
is  at  the  same  time  twisted  on  its  axis. 

The  same  succession  of  emeries  is  used  as  for  grinding  the 
larger  lenses,  but  the  polishing  is  usually  done  with  bees-wax 
hardened  with  fine  crocus,  the  wax  is  melted,  and  a  suffi- 
cient quantity  of  the  crocus  stirred  in  to  make  it  so  hard  that 
when  cold  the  finger  nail  will  only  just  indent  it.'  The  smaller 
the  lenses  the  harder  the  wax  is  made,  as  it  should  be  of  such 
a  consistence  that  with  moderate  pressure  the  wax  will  yield 
sufficiently  to  assume  the  form  of  the  lens,  and  at  the  same  time 


GRINDING    SPECULA    FOR    REFLECTING    TELESCOPES.  1274 


'    Cl( 

; 


be  so  hard  as  to  retain  the  figure  during  the  polishing.  This 
composition  has  also  been  recommended  for  larger  lenses,  but  is 
found  to  be  less  suitable  than  the  pitch  polisher,  as  when  suffi- 
ciently hard  to  retain  its  figure,  the  adhesion  is  too  great  to  be 
•mpletely  under  the  control  of  the  fingers. 
The  brass  cups  for  the  polishing  tools  of  small  lenses,  are 
urned  in  the  lathe  of  a  little  larger  radius  than  the  grindkig 
tool,  and  the  surface  is  roughened  that  it  may  the  better  hold 
the  wax,  the  tool  is  then  heated,  and  the  melted  wax  poured  in, 
and  when  cold  is  either  moulded  to  the  form  with  a  convex  tool, 
or  turned  in  the  lathe,  first  with  a  thin  scraping  tool,  and  after- 
wards finished  with  a  circular  disk,  just  as  in  turning  the  grinding 
tool.  In  polishing  the  lens  the  surface  of  the  wax  is  kept  con- 
stantly wet  with  fine  crocus  and  water,  applied  with  a  feather, 
and  the  lens  is  held  in  the  same  manner  as  for  grinding.  To 
separate  the  lenses  from  the  runner  or  handle,  they  are  warmed 
sufficiently  to  soften  the  shell-lac,  and  to  prevent  scratching  the 
lenses  in  removing  the  last  particles  of  cement,  the  latter  is 
dissolved  in  spirits  of  wine. 


The  grinding  and  polishing  of  specula  for  reflecting  telescopes 
requires  the  greatest  possible  amount  of  accuracy  and  care,  and 
is  by  far  the  most  difficult  of  all  the  processes  of  grinding  and 
polishing  for  the  production  of  form.  The  perfection  of  the 
refracting  telescope  is  in  great  measure  limited  by  the  difficulty 
of  grinding  and  polishing  the  lenses  to  the  correct  spherical 
figure,  but  an  amount  of  error  that  would  be  quite  passable  in 
the  best  lenses,  would  be  altogether  inadmissible  in  the  specula 
of  large  reflecting  telescopes,  consequently  a  very  high  degree  of 
accuracy  of  form  is  essential,  and  at  the  same  time  a  high  polish 
is  of  necessity  required  to  produce  a  reflecting  surface.  The 
ordinary  difficulties  of  producing  very  accurate  and  highly 
finished  surfaces  are  also  increased  by  the  untractable  nature  of 
the  alloy  of  which  speculums  are  formed. 

Some  remarks  on  the  composition  of  speculum  metal  have 
been  offered  at  page  270  of  the  first  volume  of  this  work,  and 
other  particulars  on  the  method  of  casting  specula  are  given  in 
the  foot  note,  pages  371-2,  and  also  in  the  Appendix,  note  F, 


J275  GRINDING    SPECULA    BY    HAND. 

page  462.  This  interesting  subject  will  be  here  followed  up  by 
some  observations  on  the  mode  by  which  the  castings,  whether  of 
small  or  large  size,  are  ground  and  polished  to  adapt  them  to  the 
telescope. 

The  process  of  grinding  and  polishing  specula  of  small  size  by 
hand  will  be  first  described,  and  the  application  of  machinery  to 
the  figuration  of  specula  of  large  and  medium  sizes,  will  be  after- 
wards adverted  to.  The  hand  process  is  subject  to  small  varia- 
tions in  the  practice  of  different  individuals,  but  these  variations 
are  made  principally  in  matters  of  detail  that  do  not  affect  the 
general  method,  or  materially  influence  the  result,  and  are  therefore 
omitted  from  the  description  to  avoid  unnecessary  complication. 

In  grinding  specula  by  hand,  the  same  general  method  of 
manipulation  is  adopted  as  for  grinding  the  best  concave  lenses, 
that  is  convex  tools  formed  of  the  same  curvature  as  the  required 
specula  are  fixed  upon  a  vertical  post,  and  the  work  is  rubbed 
upon  the  tool  with  circular  and  elliptical  strokes  in  all  directions, 
while  the  operator  continually  walks  around  the  post  to  change 
the  angle  of  the  strokes. 

The  speculum  after  having  been  carefully  annealed,  is  attached 
by  the  cement  made  of  pitch  and  wood-ashes  to  a  metal  back,  to 
support  it  during  the  working,  and  serve  for  the  attachment  of 
the  wooden  handle.  The  back  is  made  from  two-thirds  to  three- 
fourths  of  the  diameter  of  the  speculum,  and  its  face  is  made 
concave  to  exactly  fit  the  convex  side  of  the  speculum.  The 
back  has  in  the  center  a  screw  by  which  it  can  be  mounted  on  a 
lathe  to  make  the  edge  of  the  speculum  circular,  first  by  holding 
a  fine  file  to  the  revolving  edge,  and  afterwards  either  a  metal 
grinder  supplied  with  emery,  or  a  piece  of  blue  polishing  stone. 

A  pair  of  brass  templates  are  prepared  to  the  exact  radius 
required  in  the  speculum,  in  the  same  manner  as  for  lenses ;  but 
they  are  more  carefully  fitted  together.  The  rough  face  of  the 
speculum  left  from  casting  is  sometimes  removed  on  a  common 
grindstone,  turned  as  described  on  page  1108-9,  nearly  to  fit  the 
concave  template.  At  other  times  the  speculum  is  rough  ground 
with  coarse  emery,  on  an  iron  or  pewter  tool  fixed  on  the  post. 
This  grinding  is  continued  until  any  holes  in  the  surface  of  the 
casting  are  removed,  and  the  face  is  made  quite  bright. 

The  smooth  grinding  is  next  effected  with  fine  emery  upon 
convex  pewter  tool,  turned  exactly  to  fit  the  template.     This 


: 


ho 

to 
+v, 


GRINDING    SPECULA    BY   HAND.  1276 

tool  is  usually  made  circular  and  slightly  larger  than  the 
speculum.  But  the  Rev.  J.  Edwards  recommends  that  the  form 
should  be  elliptical,  in  order  that  the  same  tool  may  serve  for 

le  foundation  of  the  polisher ;  this  is  however  not  very  import- 
ant. The  smooth  grinding  is  continued  with  fine  emery  until 
the  face  of  the  speculum  is  brought  very  nearly  to  the  true 
curve.  But  however  fine  the  emery  may  be,  it  is  very  liable  to 
break  up  the  surface  of  speculum  metal  into  small  holes,  notwith- 
standing the  greatest  care,  and  therefore  as  soon  as  the  speculum 
has  been  brought  to  a  nearly  true  figure,  the  smooth  grinding 
is  discontinued,  to  avoid  the  risk  of  depreciating  the  surface. 

The  face  of  the  speculum  is  next  very  carefully  ground  to  a 
fine  surface,  and  as  true  a  figure  as  possible,  upon  a  bed  of 
hones  which  is  made  of  small  pieces  of  either  blue  polishing 
stone,  or  Water-of-Ayr  stone,  cemented  upon  a  pewter  tool 
with  pitch  and  wood  ashes.  The  stones  should  be  carefully 
selected  as  homogeneous  as  possible,  and  sawn  into  blocks  about 
three  quarters  of  an  inch  cube,  the  tool  is  warmed  to  ensure  the 
hold  of  the  cement,  which  is  then  melted  and  spread  uniformly 

er  the  surface,  the  stone  cubes  are  carefully  arranged  upon  the 
tool  in  straight  lines  about  one-eighth  of  an  inch  asunder,  and  if 
the  stones  are  of  unequal  hardness,  it  is  necessary  to  scatter  the 
hard  and  soft  pieces  as  equally  as  possible,  in  order  that  the  bed 
of  hones  may  wear  uniformly,  the  stones  should  not  however 
differ  materially  either  in  hardness  or  grain,  otherwise  the 
correct  figure  of  the  speculum  will  not  be  attained. 

After  the  stones  are  arranged  in  their  places  and  slightly 
pressed  into  the  cement,  the  interstices  are  filled  with  melted 
cement  to  within  about  a  quarter  of  an  inch  of  the  face.  The 
general  surface  of  the  bed  of  hones  is  then  turned  very  carefully 
to  the  curve  of  the  template ;  to  avoid  accident  it  may  be 
roughed  out  with  the  ordinary  sliding  rest  into  the  form  of  a 
shallow  cone,  as  the  convexity  required  is  very  slight. 

The  bed  of  hones  is  used  with  very  little  water,  and  cuts 
smoothly,  so  that  the  roughness  left  by  the  emery  may  be 
entirely  removed,  and  the  speculum  brought  to  a  very  good 
surface.  At  the  first  commencement  it  appears  to  act  very 
slowly,  but  after  the  principal  prominences  are  reduced  it  acts 
more  quickly.  Great  importance  in  the  figuration  of  the  specu- 
lum is  attached  to  the  proper  management  of  the  bed  of  hones, 


1277  POLISHING    TOOLS    FOR    SPECULA. 

which  is  applied  with  circular  and  elliptical  strokes,  exactly  the 
same  as  the  other  tools.  The  Rev.  Mr.  Edwards  says,  the  bed 
of  hones  should  be  of  a  circular  figure,  and  but  very  little  larger 
than  the  metal  intended  to  be  figured  upon  it.  "  If  the  tool  is 
made  considerably  larger  than  the  metal,  it  will  grind  the  metal 
perpetually  into  a  larger  sphere,  and  by  no  means  of  a  good 
figure,  if  the  metal  and  tool  are  of  the  same  size  exactly,  the 
metal  will  work  truly  spherical,  but  it  is  apt  to  shorten  its  focus 
less  and  less,  unless  the  metal  and  tool  are  worked  alternately 
up  wards,  4t  had  therefore  better  be  made  about  one-twentieth 
part  larger  than  the  mirror,  when  it  will  not  alter  its  focus." 

The  smoothing  with  the  bed  of  hones  is  continued  until  the 
face  of  the  speculum  is  brought  to  a  very  true  and  fine  surface, 
uniformly  bright,  it  is  then  put  into  the  tube  of  the  telescope, 
and  tried  as  to  sphericity  and  reflection,  and  any  errors  of  figure 
that  may  be  thus  detected  are  removed  by  returning  to  the  use 
of  the  bed  of  hones  as  often  as  may  be  requisite.  The  surface 
is  made  as  perfect  as  possible  with  the  hones,  in  order  to  leave 
but  very  little  to  be  effected  with  the  polisher,  as  should  the 
polishing  be  long  continued  it  is  liable  to  depreciate  the  figure  of 
the  speculum. 

Specula  are  polished  on  metal  blocks  coated  with  pitch,  or  a 
combination  of  pitch  and  resin,  materials  that  are  employed  on 
account  of  their  inelasticity. 

The  degree  of  hardness  of  the  pitch,  and  its  perfect  freedom 
from  all  impurities,  are  matters  of  primary  importance.  For 
removing  the  impurities,  the  pitch  is  carefully  washed  with  water 
and  when  melted,  strained  through  linen.  It  is  then  thickened 
by  boiling  it  slowly,  until  it  is  of  such  a  consistence  that  when 
cold  it  will  just  admit  of  being  slightly  indented  with  the  finger 
nail.  Sometimes  the  pitch  is  hardened  by  the  addition  of  about 
an  equal  quantity  of  resin,  and  this  compound  has  the  advantage 
of  being  less  brittle  than  when  pitch  of  equal  hardness  is  used, 
and  is  therefore  less  liable  to  chip  in  the  polishing.  Should  the 
pitch  be  made  too  hard,  it  may  be  softened  with  a  little  tallow. 

The  Earl  of  Rosse  employed  resin,  melted  and  mixed  with 
about  one-fifth  its  weight  of  spirits  of  turpentine  to  soften  it, 
this  was  adopted  on  account  of  the  difficulty  of  obtaining  the 
pitch  free  from  gritty  particles.  But  whether  pitch  or  resin  be 
employed,  the  hardness  requires  to  be  adjusted  with  great'care. 


POLISHING    TOOLS    FOll    SPECULA.  1278 

If  the  pitch  is  too  hard  it  will  not  readily  take  the  figure  of  the 
speculum,  and  if  too  soft  it  will  not  sufficiently  retain  the 'figure. 

In  consequence  of  the  'different  qualities  of  various  samples  of 
pitch  and  resin,  no  regular  proportions  can  be  adopted,  and  the 
degree  of  hardness  must  be  decided  experimentally  in  every  case. 

The  form  of  the  polisher  is  also  a  matter  of  considerable 
importance,  the  face  of  the  speculum  should  be  polished,  not 
strictly  spherical,  but  slightly  parabolical.  Mr.  Mudge  obtained 
an  approximation  to  the  parabolical  form  by  first  polishing  the 
speculum  as  truly  spherical  as  possible,  and  at  the  last  finish 
giving  the  speculum  a  few  large  circular  strokes  upon  the  round 
polisher,  so  as  to  increase  the  radius  of  curvature  near  the 
margin.  See  Trans.  Royal  Soc.,  Vol.  LXVII. 

The  elliptical  polisher  introduced  by  the  Rev.  John  Edwards, 
and  first  described  in  the  "Nautical  Almanack"  for  1787,  will 
however  give  a  much  nearer  approach  to  the  parabolical  form, 
without  any  other  than  straight  or  elliptical  strokes  in  all  direc- 
tions. Mr.  Edwards  speaking  of  the  proportions  of  the  ellipse 
says,  "  for  common  foci  and  apertures,  viz.  from  two-and-a-half 
to  nine-and-a-half  focus  or  3 '8  inches  in  diameter  to  eighteen 
inches  focus  the  diameters  should  be  as  ten  to  nine.  The 
shortest  diameter  of  the  ellipse  being  accurately  the  same  as  the 
diameter  of  the  metal,  ancf  the  longest  diameter  of  the  ellipse  to 
the  shortest  diameter  as  ten  to  nine."  Mr.  Edwards  also 
recommends  that  for  speculums  having  a  hole  through  the 
center,  the  polisher  should  also  have  a  hole  through  it,  of  the 
same  size  or  somewhat  less  than  the  hole  in  the  speculum,  and 
he  adds,  "  I  have  always  found  that  small  mirrors  without  any 
hole  in  the  middle,  will  polish  much  better  and  the  figure  will  be 
more  correct,  if  the  polisher  has  a  hole  in  the  middle  of  it." 

The  Earl  of  Rosse,  among  his  numerous  experiments  on  the 
grinding  and  polishing  of  specula,  tried  this  form  of  polisher, 
and  expresses  himself  as  follows  : — "  The  experiments  to  which 
I  have  alluded  were  made  with  the  elliptic  polisher  of  Mr. 
Edwards,  a  contrivance  in  my  opinion  possessing  more  merit  • 
than  has  usually  been  ascribed  to  it.  I  found  that  a  speculum  of 
four  inches  aperture  and  eighteen  inches  radius,  after  having 
been  polished  by  hand  as  truly  spherical  as  I  could  make  it,  was 
invariably  improved  by  working  it  on  the  elliptic  polisher." 

The  polisher,  generally  made  of  pewter  or  lead,  is  turned  on 


1279  POLISHING   SPECULA    BY    HAND. 


the  face  to  the  true  curve  of  the  speculum,  but  left  rough  in 
order  to  hold  the  cement.  It  is  then  warmed,  and  the  melted 
pitch  or  resin  is  very  uniformly  spread  over  its  surface  about 
one-eighth  of  an  inch  in  thickness,  and  when  the  pitch  is 
sufficiently  cooled  to  retain  the  impression  of  the  finger,  the 
speculum  is  dipped  in  water  and  pressed  firmly  upon  the  pitch 
as  in  taking  the  impression  of  a  seal.  Owing  to  the  slow  con- 
ducting power  of  the  pitch,  there  will  be  no  danger  of  the 
speculum  being  cracked  by  the  heat,  if  the  temperature  of  the 
pitch  dees  not  exceed  about  80  degrees,  although  a  slight 
difference  in  the  temperature  of  any  quickly  conducting  sub- 
stance, if  placed  directly  upon  the  speculum,  would  be  almost 
certain  to  cause  a  crack. 

When  the  polisher  has  been  moulded  to  the  form  of  the  spe- 
culum, the  rough  edges  are  pared  away  from  the  margin,  and 
also  around  the  central  hole,  if  the  polisher  have  one.  The 
surface  of  the  pitch  is  then  divided  into  small  squares  by  making 
grooves  quite  through  its  thickness  with  a  heated  knife,  to  allow 
of  the  polisher  more  readily  adapting  itself  to  the  surface  of  the 
speculum. 

The  thickness  of  the  coat  of  pitch  is  partly  dependent  on  the 
size  of  the  speculum,  and  partly  on  the  hardness  of  the  pitch : 
the  hardness  and  thickness  of  the  pitch  requiring  to  be  so 
adjusted,  that  the  polisher  will  always  yield  to  the  surface  of  the 
speculum,  so  as  exactly  to  fit  it  during  the  whole  process.  If 
the  layer  of  pitch  is  too  thin,  it  cannot  expand  laterally  to  enable 
it  to  ply  to  the  surface  of  the  speculum  ;  and  if  too  thick,  it  will 
expand  so  readily  as  not  to  retain  the  figure. 

Oxide  of  iron,  prepared  as  explained  on  page  1082,  is  in 
general  employed  for  the  polishing  of  specula.  Sometimes  the 
oxide  of  tin  is  used  ;  but  it  is  considered  to  give  a  whiter  polish, 
that  is  less  reflecting.  The  powder  is  kept  mixed  with  water  in 
a  vial,  and  applied  in  the  same  manner  as  the  polishing  powder 
for  lenses ;  but  it  is  better  to  employ  at  the  commencement  as 
much  of  the  polishing  powder  as  is  necessary  for  the  completion 
of  the  polish,  and  if  a  further  quantity  is  required,  it  should  be 
applied  as  sparingly  as  possible. 

The  speculum  is  worked  on  the  polisher  with  straight  or 
elliptical  strokes,  the  operator  continually  moving  around  the 
post  to  change  the  angle.  Sufficient  pressure  must  be  uniformly 


DIFFICULTIES    OF    POLISHING    SPECULA    BY    HAND.  1280 

applied,  to  keep  the  polisher  fitted  to  the  face  of  the  speculum. 
After  the  rubbing  has  been  continued  some  time,  the  polisher 
and  speculum  both  become  slightly  warmed  by  the  friction ;  and 
if  the  pitch  was  originally  rather  too  hard  to  copy  the  figure  of 
the  speculum  perfectly,  the  increased  warmth  will  soften  the. 
pitch,  which  will  then  ply  well  to  the  speculum,  and  the  polishing 
will  go  on  satisfactorily ;  but  if  the  pitch  becomes  too  soft,  the 
figure  of  the  speculum  ^will  be  depreciated,  and  consequently 
great  care  is  required  to  maintain  the  temperature  of  the 
polisher  as  uniform  as  possible,  and  just  sufficient  to  keep  the 
pitch  in  good  working  condition.  Sometimes  the  polisher  is 
very  slightly  warmed  before  applying  it  to  the  speculum. 

The  method  of  grinding  and  polishing  specula  by  hand  is  at 
all  times  very  difficult,  and  the  results  very  uncertain,  even 
with  those  of  four  or  five  inches  diameter ;  as  although  it  is 
comparatively  easy  to  figure  the  specula  so  accurately  to  the 
general  form  that  no  errors  can  be  detected  by  mechanical 
means,  yet,  when  tried  in  the  telescope,  it  frequently  happens 
that  so  many  minute  errors  are  presented  in  the  speculum,  that 
the  reflection  appears  quite  undefined,  and  of  course,  in  this  con- 
dition, the  speculum  is  unfit  for  its  intended  purpose. 

The  principal  sources  of  error  apparently  inseparable  from 
hand-polishing  are,  the  absence  of  exact  control  in  regulating 
the  lengths  and  directions  of  the  strokes,  irregular  increase  of 
temperature  in  the  speculum  and  polisher,  unavoidably  caused 
by  the  friction  ;  and  also  the  unequal  pressure  of  the  hand.  All 
these  difficulties  rapidly  increase  with  an  enlargement  of  size ; 
and  a  speculum  of  six  or  eight  inches  diameter  is  perhaps  as 
large  as  can,  with  the  utmost  care,  be  produced  by  hand  with  the 
required  accuracy.  Larger  specula  have  occasionally  been 
polished  by  hand ;  but  in  the  majority  of  instances  it  has  ulti- 
mately proved  that  the  increased  incorrectness  of  defining  power, 
has  to  a  considerable  extent  counterbalanced  the  advantages 
derived  from  an  increase  of  diameter. 

With  the  view  of  avoiding  the  uncertainties  of  the  hand- 
process,  the  Earl  of  Rosse  constructed  a  machine  for  grinding 
and  polishing  specula,  in  which  the  different  motions  were  sus- 
ceptible of  separate  adjustments,  and  were  all  under  complete 
control.  A  sketch  of  this  machine  was  published  in  Sir 
D.  Brewster's  Journal  for  October,  1828.  The  machine  was 


1281 


THE    EARL    OF    ROSSE  S    MACHINE 


subsequently  improved  and  enlarged,  so  as  to  be  capable  of  work- 
ing a  speculum  of  three  feet  diameter ;  and  from  an  experience  of 
many  years,  during  which  specula  were  polished  with  it  many 
hundred  times  with  great  accuracy,  it  was  found  perfectly  suc- 
xcessful  in  producing  large  specula  with  a  degree  of  precision 
quite  unattainable  by  hand,  even  by  accident. 

The  machine  is  shown  in  fig.  1132,  copied  from  his  Lordship's 
paper  on  the  reflecting  telescope,  published  in  the  Philosophical 
Transactions  of  the  Royal  Society  for  1840,  from  which  the 


annexed  description  is  also  extracted : — "  A  is  a  shaft  connected 
with  a  steam-engine  ;  B,  an  eccentric,  adjustable  by  a  screw- 
bolt,  to  give  any  length  of  stroke  from  0  to  18  inches ;  C,  a 
joint ;  D,  a  guide  ;  E  F,  a  cistern  for  water,  in  which  the  spe- 
culum revolves ;  G,  another  eccentric,  adjustable,  like  the  first, 
to  any  length  of  stroke  from  0  to  18  inches.  The  bar  D  G 
passes  through  a  slit,  and  therefore  the  pin  at  G  necessarily 
turns  on  its  axis  in  the  same  time  as  the  eccentric.  H  I  is  the 
speculum  in  its  box,  immersed  in  water  to  within  one  inch  of  its 
surface  ;  and  K  L,  the  polisher,  which  is  of  cast  iron,  and  weighs 
about  two  and  a  half  hundred  weight.  M  is  a  round  disk  of 
wood,  connected  with  the  polisher  by  strings  hooked  to  it  in  six 
places,  each  two-thirds  of  the  radius  from  the  centre.  At  M 
there  is  a  swivel  and  hook,  to  which  a  rope  is  attached  connecting 


FOR    GRINDING    AND    POLISHING    SPECULA.  1282 

the  whole  with  the  lever  N,  so  that  the  polisher  presses  upon  the 
speculum  with  a  force  equal  to  the  difference  between  its  own 
weight  and  that  of  the  counterpoise  O.  For  a  speculum  three 
feet  diameter  I  make  the  counterpoise  ten  pounds  lighter  than 
the  polisher.  The  bar  D  G  fits  the  polisher  nicely,  but  without 
tightness,  so  that  the  polisher  turns  freely  round,  usually  about 
once  for  every  fifteen  or  twenty  revolutions  of  the  speculum,  and 
it  is  prevented  by  four  guards  from  accidentally  touching  the 
speculum,  and  from  pressing  upon  the  polisher  by  the  two  guides 
through  which  its  extremities  pass.  In  fig.  1131  this  bar  is  on  a 
larger  scale.  I  have  used  a  variety  of  contrivances  for  connecting 
the  machinery  with  the  polisher ;  but  the  one  I  have  described 
is  by  far  the  best.  The  wheel  B  makes,  when  polishing  a  three- 
feet  speculum,  sixteen  revolutions  in  a  minute  ;  to  polish  a  smaller 
speculum,  the  velocity  is  increased  by  changing  the  pulley  on  the 
the  shaft  A.  The  machine  is  in  a  room  at  the  bottom  of  a  high 
tower,  and  doors  can  be  opened  in  the  successive  floors,  so  that 
a  dial-plate  of  a  watch  placed  perpendicularly  over  the  speculum 
can  be  examined  at  any  moment.  The  dial-plate  is  attached  to 
a  mast,  so  as  to  be  much  higher  than  the  tower,  and  about  ninety 
feet  from  the  speculum ;  and  a  small  flat  metal  and  eye-piece, 
with  its  proper  adjustments,  completes  the  arrangements  for  a 
Newtonian  telescope." 

The  machine  is  driven  by  flat  leather  bands,  as  shown  in  the 
figure,  an  inspection  of  which  will  readily  explain  the  action  of 
the  machine.  The  cast  iron  polisher  is  used  first  with  emery  and 
water  for  the  grinding,  and  is  afterwards  coated  with  resinous 
cement  for  polishing,  the  intermediate  process  of  the  bed  of 
hones  not  being  required  with  the  machine.  No  material  difficulty 
was  experienced  in  grinding  the  speculum  to  the  spherical  form ; 
but  some  adjustments  are  required  for  obtaining  the  parabolical 
figure.  The  elliptical  polisher  of  Mr.  Edwards,  although  so 
valuable  for  figuring  small  specula  by  hand,  was  found  to  fail 
with  large  specula,  from  the  radius  of  curvature  being  increased 
too  rapidly  near  the  edge.  Speaking  of  this  adjustment,  the 
Earl  of  Rosse  says  : — 

"  Having  observed  that  when  the  extent  of  the  motions  of  the 
polishing  machine  were  in  certain  proportions  to  the  diameter  of 
the  speculum,  its  focal  length  gradually  and  regularly  increased, 
that  fact  suggested  another  mode  of  working  an  approximate 

VOL.  III.  S 


1283  THE   EARL    OF    ROSSE^S    MACHINE 

parabolical  figure.  If  we  suppose  a  spherical  surface,  under  the 
operation  of  grinding  and  polishing,  gradually  to  change  into  one 
of  longer  radius,  it  is  very  evident  that,  during  the  change,  at  no 
one  instant  of  time  will  it  be  actually  spherical,  and  the  abrasion 
of  the  metal  will  be  more  rapid  at  each  point  as  it  is  more  distant 
from  the  center  of  the  face.  When,  however,  the  focal  length 
neither  increases  nor  diminishes,  the  abrasion  will  become  uniform 
over  the  whole  surface,  producing  a  spherical  figure.  According, 
however,  as  the  focal  length  (the  actual  amount  of  abrasion 
during  a  given  time  being  given)  increases  more  or  less  rapidly, 
the  nature  of  th<3  curve  will  vary,  and  we  might  conceive  it 
possible,  having  it  in  our  power  completely  to  control  the  rate 
at  which  the  focal  length  increases,  so  to  proportion  the  rate  of 
increase  as  to  produce  a  surface  approximating  to  that  of  the 
paraboloid.  Of  course,  the  chances  against  obtaining  an  exact 
paraboloid  are  infinitely  great,  as  an  infinite  number  of  curves 
may  pass  between  the  parabola  and  its  circle  of  curvature,  and  it 
is  vain  to  look  for  a  guide  in  searching  for  the  proper  one  in  cal- 
culations founded  on  the  principles  of  exact  science,  as  the  effect 
of  friction  in  polishing  is  not  conformable  to  any  known  law; 
still  from  a  number  of  experiments  it  might  be  possible  to  deduce 
an  empirical  formula  practically  valuable :  this  I  have  endeavoured 
to  accomplish." 

"  The  weight  of  the  polisher  was  constant,  being  the  least 
possible  consistent  with  its  working  properly,  viz.,  ten  pounds  for 
a  speculum  three  feet  diameter. 

"  The  distance  of  the  counterpoising  lever  would  obviously 
influence  the  curve ;  that  I  have  regarded  as  constant  also,  viz. 
twelve  feet ;  as  also,  in  all  my  most  recent  experiments  the  length 
of  stroke  of  the  first  eccentric  B,  which  was  one-third  of  the 
diameter  of  the  speculum ;  the  only  variable  quantity  was  there- 
fore the  stroke  of  the  second  eccentric  G.  Under  these  circum- 
stances, the  most  accurate  determination  at  which  I  have  been 
enabled  to  arrive  is,  that  when  the  stroke  of  the  second  eccentric 
G  is  such  as  to  communicate  a  lateral  motion  to  the  polisher  equal 
to  about  *27  of  the  diameter  of  the  speculum,  the  curve  will  be 
nearly  parabolic."  The  figure  of  the  speculum  is  tested  during 
the  grinding  and  polishing,  by  observing  the  reflection  of  the 
watch-dial,  and  the  adjustment  of  the  length  of  stroke  admits  of 
being  made  with  such  accuracy,  that  the  three  feet  speculum 


FOR    GRINDING    AND    POLISHING    SPECULA. 


1284 


"  with  its  whole  aperture,  is  thrown  perceptibly  out  of  focus  by  a 
motion  of  the  eye-piece,  amounting  to  less  than  the  thirtieth  of 
an  inch  :  and  even  with  a  single  lens  of  an  eighth  of  an  inch  focus, 
giving  a  power  of  2592,  the  dots  on  a  watch-dial  are  still  in  some 
degree  defined." 

Much  difficulty  was  experienced  in  the  management  of  the 
resinous  composition  for  the  surface  of  the  polisher,  the  necessity 
for  increasing  the  thickness  of  the  composition  in  proportion  to 
the  size  of  the  speculum  was  in  itself  sufficient  to  prevent  great 
accuracy  being  attained.  This  was  first  endeavoured  to  be  over- 
come by  dividing  the  surface  of  the  composition  with  a  heated 
iron  into  squares,  but  although  this  greatly  improved  the  figure 
of  the  speculum  by  allowing  of  the  lateral  expansion  of  a  thin 
layer  of  the  resinous  composition,  it  was  found  that  the  spaces 
soon  filled  up,  and  the  same  difficulty  then  returned.  This 
defect  was  entirely  remedied  by  dividing  the  iron  disk  itself 
instead  of  the  cement.  Several  polishers  were  made  on  this 
construction,  in  which  the  arrangement  and  dimensions  of  the 
grooves  were  varied,  but  the  form  ultimately  preferred  is 
shown  in  figs.  1133  and  1134,  which  represent  the  face  and 


FIG.  1133. 


FIG.  1134. 


back  views  of  the  polisher.  "  The  circular  grooves  were  turned 
with  the  slide  rest,  and  are  three-eighths  of  an  inch  deep  and 
one  quarter  wide,  leaving  bands  of  continuous  surface  one 
quarter  of  an  inch  wide.  The  grooves  at  right  angles  are  about 
one  inch  and  a  quarter  distant,  one  quarter  of  an  inch  wide 
and  half  an  inch  deep,  cut  with  the  circular  saw.  The  speculum 
was  of  course  truly  ground  with  the  polisher  first,  and  then 

s2 


1285  THE    EARL    OP    ROSSE^S    MACHINE 

the  layer  of  resinous  composition  applied,  the  grooves  remaining 
empty. 

There  was  still  a  difficulty  with  respect  to  the  hardness  of  the 
resinous  composition ;  on  the  one  hand  it  is  essential  to  the  truth 
of  the  general  figure  that  the  composition  should  be  soft  enough 
to  expand  laterally  to  enable  it  to  fit  the  speculum,  on  the  other 
hand  the  composition  is  required  to  be  as  hard  as  is  consistent 
with  the  polishing  powder  being  able  to  embed  itself  in  its  surface, 
in  order  that  the  face  of  the  speculum  may  be  equally  acted  upon 
by  the  polisher,  notwithstanding  minute  differences  in  the  texture 
of  the  metal  at  different  parts.  The  Earl  of  Rosse  found  that 
the  two  properties  apparently  inconsistent  with  each  other,  could 
be  imparted  to  the  polisher  at  the  same  time,  simply  by  using  the 
resinous  composition  of  two  degrees  of  hardness,  so  as  to  form 
two  very  thin  strata,  the  outer  one  being  the  harder. 

For  the  preparation  of  the  composition  "  common  resin  is 
melted,  and  when  nearly  boiling,  spirit  of  turpentine  is  added  to 
it,  perhaps  about  one-fifth  of  its  weight ;  but  resin  varies  so  much 
in  quality,  that  there  is  no  guide  except  trial.  When  the  mixture 
has  been  incorporated  by  stirring,  a  cold  piece  of  iron  is  to  be 
immersed  in  it,  and  then  placed  for  some  minutes  in  a  vessel  of 
water,  at  a  temperature  of  55° ;  if  then  a  moderate  pressure  of 
the  nail  makes  a  decided  impression  without  splintering,  it  is  of  a 
proper  hardness  for  the  first  layer  on  the  polisher,  and  only 
requires  to  be  strained  through  canvass." 

"  For  the  second  layer,  it  is  mixed  with  one  fourth  of  wheat 
flour,  which  by  increasing  its  tenacity  and  diminishing  its 
adhesiveness,  prevents  that  accident  so  much  complained  of  by 
practical  men,  viz.,  the  separation  of  minute  particles  of  pitch 
from  the  polisher,  which  afterwards  run  loose  between  the 
polisher  and  the  speculum.  It  is  to  be  boiled  till  the  water  of 
the  flour  has  been  expelled,  and  the  mixture  becomes  clear,  and 
the  boiling  further  continued  till  some  of  the  turpentine  has 
been  driven  off,  and  the  mixture  has  become  so  hard,  that  at  a 
temperature  of  55°,  a  very  strong  pressure  of  the  nail  makes 
but  a  slight  impression :  it  is  still  too  soft,  and  I  then  add  to  it 
an  equal  weight  of  resin  ;  it  will  then  be  hard  enough  to  produce 
a  very  true  surface  and  at  the  same  time,  soft  enough  to  suffer 
the  particles  of  polishing  powder  to  embed  themselves,  and  con- 
sequently  to  produce  a  very  fine  black  polish.  Whenever  the 


I 


FOR    GRINDING    AND    POLISHING    SPECULA.  1286 

resinous  mixture  is  remelted,  I  suspend  the  vessel  to  the  beam 
of  a  scale,  counterpoise  it,  and  take  care  to  apply  the  heat  so 
gradually  as  not  to  drive  off  any  of  the  turpentine,  which  is  imme- 
diately perceptible  by  the  disturbance  of  the  equilibrium." 

"  To  apply  the  resin,  the  polisher  is  first  heated  to  about  150° 
and  the  soft  mixture  laid  on  with  a  large  flat  brush,  to  about 
the  thickness  of  about  one-thirtieth,  or  one  twenty-fifth  of  an 
inch ;  it  is  then  suffered  to  cool  to  about  100°,  and  the  hard 
mixture  applied  in  the  same  way  and  to  about  the  same  thick- 
ness. When  the  temperature  has  sunk  to  80°,  the  polisher  is 
)laced  on  the  speculum  previously  covered  with  peroxide  of  iron 
and  water,  of  about  the  consistence  of  thin  cream." 

The  Earl  of  Rosse  found  that  the  quality  of  the  polish  which 
yields  the  maximum  of  defining  power  is  that  technically  called 
a  black  polish,  provided  a  very  fine  grain  is  perceptible  when 
the  speculum  is  placed  near  a  window.  A  speculum  may  be 

>lished  so  that  its  surface  appears  without  grain  like  quicksilver, 
but  it  is  necessary  for  this  purpose  to  employ  a  softer  resinous 
cement  than  appears  consistent  with  a  very  true  surface,  and  the 
Earl  of  Rosse  considers  the  best  chance  of  improving  the  polish 
would  be  to  search  for  some  polishing  substance  consisting  of 
smaller  particles  than  the  fine  peroxide  of  iron,  so  as  to  produce 
a  grain  not  exceeding  the  magnitude  which  theory  has  assigned 
as  that  of  an  undulation  of  light. 

As  shown  in  fig.  11 32,  the  speculum  revolves  face  upwards  within 
le  water  cistern  E,  F,  and  this  cistern  being  nearly  filled  with 
fater  kept  at  a  temperature  of  55°  no  unequal  expansion  of  the 
speculum  from  increase  of  temperature  can  take  place,  and  the 
)itch  being  also  maintained  at  the  same  temperature  as  that  at 
rhich  it  was  first  adjusted,  does  not  become  softened  during  the 
>olishing  as  in  the  hand  process. 

In  grinding  and  polishing  the  gigantic  speculum  of  6  feet 
liameter,  the  Earl  of  Rosse  employed  the  same  general  arrange- 
nent  of  apparatus  as  that  used  for  the  3  feet  speculum ;  but 
from  the  increased  dimensions,  some  modifications  were  required, 
most  important  of  which  were  noticed  in  a  lecture  on 
large  reflecting  telescopes,  delivered  by  the  Astronomer  Royal 
before  the  Astronomical  Society,  and  the  substance  of  which  was 
published  in  their  Memoirs  for  March,  184.9.  From  this,  it 
appears  that,  in  figuring  the  6  feet  speculum,  the  circular 


1287  THE    EARL    OF    ROSSE^S    MACHINE 

grooves  in  the  cast-iron  polisher  were  omitted,  and  the  straight 
grooves  at  right  angles  were  made  about  1  inch  deep,  and 
2  inches  asunder,  so  as  to  divide  the  surface  into  squares.  The 
weight  of  the  polisher  was  uniformly  supported  at  twelve  points, 
the  piece  M,  fig.  1132,  being  made  triangular,  with  a  pulley  at 
each  corner ;  a  cord  was  passed  over  every  pulley,  and  each  end 
of  the  cord  supported  the  middle  of  a  straight  lever,  the  ends  of 
which  were  attached  to  the  polisher. 

In  the  rough  grinding,  the  great  weight  of  the  iron  disk,  and 
the  brittle  nature  of  the  speculum  metal,  rendered  the  placing  of 
the  grinder  upon  the  mirror  highly  dangerous,  as  the  slightest 
jar  of  the  grinder  upon  the  speculum  would  have  been  liable  to 
break  the  latter.  To  avoid  this  risk,  a  number  of  thin  wooden 
wedges  were  placed  upon  the  margin  of  the  speculum;  the 
polisher  was  slowly  lowered  upon  the  wedges,  and  then,  by 
degrees,  they  were  gently  withdrawn. 

In  the  machine  shown  in  fig.  1132,  the  bar,  D  G,  passing 
through  the  fixed  guide,  D,  at  one  end,  and  through  the 
revolving  guide,  G,  at  the  other,  communicates  a  slow  lateral 
motion  to  the  grinder,  alternately  to  the  right  and  left.  "  But 
as,  in  the  ordinary  crank  motion,  the  duration  of  the  strokes  at 
the  extreme  right  and  left  would  be  too  great,  the  wheel  on  the 
spindle  of  this  grinding  crank  is  elliptical,  the  proportion  of  its 
axes  being  about  three  to  one  ;  its  angular  motion  is,  therefore, 
unequal ;  and  the  strokes  are  thus  made  to  dwell  a  shorter 
time  near  the  extreme  right  and  left,  and  a  longer  time  near 
the  center." 

In  polishing  the  speculum,  it  was  found  that  not  only  should 
the  temperature  of  the  air  in  the  polishing  room  be  maintained 
nearly  uniform  during  the  process,  in  order  to  prevent  the  irre- 
gular expansion  of  the  speculum,  but  also  that  it  was  essential 
that  the  degree  of  moisture  in  the  air  should  be  such,  that  the 
wet  polishing  powder  should  gradually  dry  at  the  proper  rate. 
The  polishing  is  therefore  not  attempted  when  the  air  in  the 
room  is  too  damp,  and  should  the  air  be  too  dry,  it  is  moistened 
by  a  jet  of  steam.  After  the  process  had  been  continued  about 
eight  hours,  the  polisher  is  removed,  and  a  fresh  application  is 
made  of  the  polishing  powder  mixed  with  "  ammonia  soap," 
substance  formed  by  treating  common  soap  with  ammonia.  Tl 
dries  more  rapidly  than  the  powder  mixed  with  water  alone,  ai 


FOR    SUPPORTING    SPECULA    IN    TELESCOPES.  1288 

the  polishing  is  continued  until  the  surface  of  the  metal  is  very 
?arly  dry,  the  'process  is  then  considered  to  be  completed,  and 
polisher  is  taken  off  the  speculum  to  allow  of  its  inspection. 


In  the  figuration  of  small  specula  by  hand,  the  metal  is  usually 
ittached  by  cement  to  a  temporary  back,  which  serves  as  the 
ipport  during  the  grinding  and  polishing,  and  is  removed  before 
the  speculum  is  placed  in  the  telescope,  but  even  with  small 

icula  there  is  always  some  risk  of  distorting  or  breaking  the 
speculum  in  the  act  of  detaching  the  back,  and  it  is  therefore  at 
all  times  the  better  practice,  to  form  the  back  in  such  a  manner, 
that  it  may  remain  permanently  attached  to  the  speculum,  and 
constitute  its  bed  in  the  telescope.  Larger  specula,  unless  uni- 
formly supported  at  all  times,  are  liable  to  flexure,  which  would 
destroy  the  accuracy  of  figure  given  by  grinding ;  it  is  therefore  of 
the  first  importance  that  the  larger  specula  should  be  ground  and 
polished  in  the  same  bed  that  is  to  be  employed  in  the  telescope. 

To  prevent  flexure  in  specula  of  moderate  dimensions,  the 
Earl  of  Rosse  found  it  quite  sufficient  to  support  them  in  their 
box,  on  three  strong  iron  plates,  each  plate  being  one-third  part 
of  a  circular  area,  the  same  size  as  the  speculum,  and  a  sector  of 
it ;  the  plates  rest  at  their  centers  of  gravity,  on  points  fixed 
at  the  bottom  of  the  box  of  the  speculum,  and  therefore  no 
flexure  of  the  box  can  affect  the  speculum.  In  supporting  the 
speculum  of  3  feet  diameter,  Lord  Rosse  attached  nine  plates 
to  the  speculum,  every  group  of  three  being  supported  at  their 
centers  of  gravity  upon  a  triangle,  having  three  points  to  sustain 
the  pressure,  and  the  center  of  every  triangle  is  supported  upon 
one  of  three  points  in  the  bottom  of  the  box.  The  6  foot  spe- 
culum is  supported  in  a  similar  manner,  upon  twenty-seven  cast- 
iron  plates,  sustained  upon  a  series  of  nine  triangles,  that  are 
again  supported  upon  three  triangles,  the  centers  of  which  rest 
upon  three  points.  The  twenty-seven  plates  were  originally 
attached  to  the  speculum  by  felt  and  pitch,  but  when  the  telescope 
was  placed  at  different  inclinations,  it  was  found  that  the  reflec- 
tion was  distorted,  owing  to  the  speculum  having  a  slight  motion 
edgeways,  which  threw  some  of  the  points  of  bearing  partially 
out  of  contact.  This  difficulty  has  been  overcome  by  removing 


1289         MR.  LASSELL'S  MACHINE  FOR  POLISHING  SPECULA. 


the  layer  of  pitch  and  felt,  by  which  the  plates  were  attached  to 
the  speculum,  and  substituting  sheets  of  tin,  which  allow  the 
speculum  to  slide  a  small  distance  upon  the  plates. 


'-  A  very  valuable  machine,  of  a  different  construction,  for 
polishing  specula,  has  been  contrived  by  Mr.  William  Lassell, 
of  Starfield,  near  Liverpool.  The  attention  of  this  gentleman 
has  been  for  many  years  devoted  to  the  construction  of  reflecting 
telescopes,  and  his  success  in  figuring  by  hand  specula  of  all 
sizes,  up  to  9  inch  diameter  and  9  feet  focal  length,  led  him  to 
conceive  the  idea  of  constructing  a  telescope  with  a  speculum  of 
2  feet  diameter,  and  20  feet  focal  length. 

As  a  preliminary  step  to  the  construction  of  the  speculum, 
Mr.  Lassell.  inspected  Lord  Rosse's  laboratory,  and  the  per- 
formance of  the  machinery  for  grinding  and  polishing  specula 
appeared  so  satisfactory,  that  Mr.  Lassell  determined  to  employ 
a  similar  machine  for  polishing  his  2  foot  speculum.  "  But 
finding,  after  many  months'  trial,  that  he  could  not  succeed  in 
obtaining  a  satisfactory  figure,  he  was  led  to  contrive  a  machine 
for  imitating  as  closely  as  possible  those  evolutions  of  the  hand 
by  which  he  had  been  accustomed  to  produce  perfect  surfaces  on 
smaller  specula."  The  idea  of  the  machine  was  communicated 
by  Mr.  Lassell  to  his  friend  Mr.  James  Nasmyth,  of  Patricroft, 
near  Manchester,  by  whom  the  mechanical  details  were  designed, 
and  the  machine  constructed  on  the  beautiful  arrangement  shown 
in  fig.  1135,  which  is  copied  from  a  drawing  kindly  supplied  by 
Mr.  Nasmyth,  and  we  are  also  indebted  to  the  same  gentleman 
for  the  annexed  description,  which  he  has  obligingly  written  for 
these  pages. 

"  The  power  is  conveyed,  in  the  first  instance,  by  a  band  or 
belt,  to  the  pulley  A,  which  conveys  motion  by  the  endless  screw 
B,  to  the  wheel  C.  The  spindle  of  the  wheel  C,  viz.,  D,  has 
made  fast  to  it,  a  crank,  or  arm,  E,  which  carries  a  pinion  F, 
and  causes  the  pinion  to  revolve  round  the  toothed  circumfer- 
ence of  the  wheel  G,  which  wheel  G  being  fixed  to  the  bracket 
H,  causes  the  pinion  F  to  revolve  with  as  many  turns  as  its 
circumference  is  less  than  that  of  the  wheel  G,  viz.,  5  to  1. 

"  As  the  spindle  of  the  pinion  F,  has  a  wheel  K,  fixed  to  it  at 


MR.  LASSELL'S  MACHINE  FOR  POLISHING  SPECULA.         1290 

FIG.  1135. 


1291         MB.  LASSELL'S  MACHINE  FOR  POLISHING  SPECULA. 

its  lower  end,  this  wheel  K  will,  in  like  manner,  convey  motion 
to  the  pinion  L,  which  works  on  an  adjustable  center  pin,  and  as 
the  T  groove  in  which  the  center  pin  of  L  works,  is  radial  to  the 
center  of  the  wheel  K,  this  pinion  may  be  set  to  any  degree  of 
eccentricity,  and  yet  be  in  gear  with  K. 

"  It  will  also  be  seen  that  the  pinion  L  has  a  cross  crank,  M, 
attached  to  its  under  side,  which,  having  its  crank  pin,  N,  also  slid- 
ing in  a  T  groove,  it  may  be  set  to, 
and  fixed  at,  any  degree  of  eccentri- 
city, so  that  we  have  by  these  two 
eccentric  movements  the  means  of 
giving  to  the  pin  N,  any  compound 
motion  we  require. 

"  The  polisher  is  of  wood,  or 
other  suitable  material  coated 
with  pitch,  and  divided  into 
squares.  This  polisher  is  free  to 
move  upon  the  pin  N,  while  N 
causes  the  polisher  to  slide  over 

the  surface  of  the  speculum  with  a  motion  somewhat  like  that 
shown  in  fig.  1136. 

"  In  order  to  cause  every  part  of  the  surface  of  the  speculum 
to  continually  change  its  situation  with  respect  to  the  move- 
ments of  the  polisher,  it  has  also  a  slow  revolving  motion  given 
by  an  endless  screw,  P,  pitched  or  working  into  the  teeth  of  the 
wheel  R,  which  forms  the  base  on  which  the  speculum  rests, 
while  receiving  the  action  of  the  polisher. 

"  The  speculum  rests  on  nine  equilibrium  points  so  that  each 
ninth  of  its  body  is  made  to  rest  on  a  point  or  surface  placed 
under  the  center  of  gravity  of  each  ninth  of  the  speculum  surface, 
and  so  avoid  all  risk  of  distortion.  It  is  the  best  practice  to 
polish  the  speculum  while  resting  in  the  cell  in  which  it  is  to  be 
when  actually  in  the  telescope,  so  as  no  risk  of  distortion  may 
occur,  as  would  be  the  case  were  it  removed,  after  polishing,  into 
another  cell  or  bed. 

"  By  means  of  this  admirable  machine,  a  speculum  having  a 
decidedly  hyperbolic  figure  may  be  corrected  and  brought  to  a 
perfect  parabola,  or  to  a  spherical  curve,  or  the  same  may  be 
done  in  the  reverse  order  at  pleasure.  A  stronger  proof  of  the 
perfect  capabilities  of  Mr.  LasselPs  machine  could  not  be  given." 


DR.  GREENE'S  MACHINE  FOR  POLISHING  SPECULA.          1292 

From  the  foregoing  description  it  will  be  seen  that  the  essen- 
tial difference  between  the  machines  contrived  by  Lord  Rosse 
and  Mr.  Lassell,  is  that  in  the  former,  the  polisher  is  traversed 
over  the  speculum  with  reciprocating  longitudinal  motion,  and 
in  the  latter,  the  polisher  has  a  continuous  epitrochoidal  motion, 
the  path  of  which  is  dependent  upon  the  adjustments  of  L  and 
M.  Mr.  Lassell's  polisher  was  made  of  two  thicknesses  of  pine 
wood,  with  the  grain  crossed ;  this,  from  its  lightness,  did  not 
require  to  be  counterpoised,  and  apparently  from  its  being  suffi- 
ciently yielding  to  accommodate  itself  somewhat  to  the  form  of 
the  speculum,  a  single  coating  of  pitch  was  found  sufficient,  and 
the  polishing  was  completed  with  wet  powder. 

Very  complete  evidence  of  the  perfection  of  the  speculum 
polished  in  this  machine  is  afforded  by  the  circumstance,  that 
with  the  telescope  to  which  it  was  fitted,  Mr.  Lassell  discovered 
the  satellite  of  Neptune,  the  eighth  satellite  of  Saturn,  and 
re-observed  the  satellites  of  Uranus,  which  latter,  since  their 
announcement  by  Sir  W.  Herschel  had  been  seen  by  no  other 
observer.  These  results  have  already  arisen  from  the  employ- 
ment of  Mr.  LasselPs  admirable  contrivance  and  dexterity  in  the 
management  of  his  polishing  machine,  and  his  excellent  skill  as 
an  observer,  in  conjunction  with  a  very  perfect  and  powerful 
instrument,  which  has  resulted  principally  from  his  own  skilful 
exertions.  The  high  value  attached  to  these  contributions  to 
science,  is  evidenced  by  the  circumstance  that  the  Royal  Astro- 
nomical Society  awarded  their  gold  medal  for  1848  to  Mr. 
Lassell. 

Since  the  Earl  of  Rosse  has  shown  that  contrary  to  the 
previous  general  opinion,  specula  may  be  successfully  polished 
by  mechanical  means,  other  machines  have  been  constructed  for 
the  same  purpose,  but  have  not  been  applied  to  specula  of  such 
large  dimensions.  In  Dr.  R.  Greene's  machine  for  grinding 
and  polishing  specula  and  lenses,  rewarded  by  the  Society  of 
Arts  in  1834  (See  Trans.,  Vol.  L.,  p.  140),  the  polisher  is 
mounted  on  a  very  slowly  revolving  axis,  and  the  speculum  also 
revolving  slowly,  but  at  a  different  rate,  is  traversed  over  the 
polisher  by  means  of  a  central  pin,  joined  to  the  extremities 
of  two  horizontal  connecting  rods  at  right  angles  to  each  other, 
actuated  by  two  cranks,  the  relative  velocities,  length  of  stroke, 
and  angular  positions  of  which  all  admit  of  adjustment,  and  con- 


1293 


MR.  HODGSON  S    APPARATUS    FOR 


sequently  the  mirror  can  be  traversed  over  the  polisher  in  ai 
infinite  variety  of  curves, 

A  very  simple  machine  for  grinding  and  polishing  specula  of 
small  size  has  been  contrived  by  the  Rev.  William  Hodgson, 
M.A.,  of  Brathay,  who  has  followed  the  general  principles  intro- 
duced by  Lord  Rosse,  but  has  arranged  the  machine  on  the 
foundation  of  an  ordinary  turning  lathe,  driven  by  a  foot-wheel, 
which,  with  the  common  overhead  motion,  and  a  part  of  the 
horizontal  grinding  machine  shown  in  fig.  1039,  page  1157, 
forms  the  principal  portion  of  his  polishing  machine  for  specula. 
This  contrivance,  therefore,  possesses  the  recommendation  of 
being  composed,  in  great  measure,  of  the  ordinary  apparatus 
possessed  by  most  amateurs,  and  may  be  readily  fitted  up  for  an 
occasional  purpose,  in  those  cases  which  would  scarcely  be  con- 
sidered of  sufficient  importance  to  call  for  the  construction  of 
the  more  elaborate  machines  of  Lord  Rosse  or  Mr.  Lassell. 

Fig.  1137  represents  a  modification  of  the  arrangement  of 
Mr.  Hodgson^s  machine ;  the  cast-iron  frame,  a,  carrying  the 


FIG.  1137. 


GRINDING    AND    POLISHING    SM4LL    SPECULA.  1294 

vertical  mandrel  of  the  horizontal  grinding  machine,  is  fixed  at 
the  back  of  the  lathe-bearers,  either  by  a  bolt  passing  through 
the  bearer ;  or  a  short  supplementary  bearer  is  fixed  at  the 
back,  and  the  frame  is  held  by  a  wedge  beneath,  as  shown  in 
fig.  1039.  The  speculum  is  mounted  on  a  chuck,  b,  fixed  on 
the  screw  of  the  vertical  mandrel,  in  the  usual  manner,  and  the 
edge  of  the  chuck  is  cut  as  a  screw-wheel,  which  is  driven  by  a 
tangent  screw,  mounted  between  the  mandrel  and  popit-head  of 
the  lathe,  and  by  which  a  slow  rotatory  motion  is  given  to  the 
speculum,  c.  The  polisher,  which  is  placed  upon  the  speculum, 
is  encircled  by  a  loose  ring,  precisely  similar  to  that  employed  in 
Lord  Rosse's  machine,  and  a  reciprocating  motion  is  given  to 
the  ring,  which  allows  of  the  very  slow  rotation  of  the  polisher, 
exactly  as  in  Lord  Rosse's  arrangement. 

The  reciprocating  motion  of  the  polisher  across  the  face  of 
the  speculum  is  obtained  after  the  method  adopted  by  Professor 
Willis  for  giving  a  reciprocating  motion  to  his  vertical  sawing 
machine,  shown  in  fig.  729,  Vol.  II.,  the  only  changes  being  those 
required  in  the  alteration  of  the  motion  from  the  vertical  to  the 
horizontal  position.  For  this  purpose  the  spindle  of  the  over- 
head motion  is  fitted  with  an  adjustable  eccentric,  shown  at  d, 
a  loop  encircles  the  eccentric,  and  terminates  in  a  catgut  band 
that  passes  under  the  guide  pulley  e,  and  is  connected  to  the 
front  of  the  ring  embracing  the  polisher.  A  second  band  pro- 
ceeds from  the  back  of  the  ring,  and  is  connected  to  a  vertical 
steel  spring,  f,  fixed  at  the  back  of  the  lathe. 

Motion  is  communicated  to  the  lathe  mandrel,  by  the  band 
leading  to  the  foot  wheel  in  the  ordinary  manner,  and  a  second 
band  is  led  to  the  over-head  motion,  either  from  the  foot  wheel, 
as  shown  in  the  figure,  or  from  the  pulley  of  the  mandrel.  The 
relative  velocities  of  the  polisher  and  speculum,  may  be  readily 
adjusted  by  shifting  the  bands  to  different  grooves  on  the  driving 
pulleys,  and  the  length  of  stroke  of  the  polisher  is  adjusted  by 
shifting  the  position  of  the  eccentric,  which,  as  seen  in  the  figure, 
is  fixed  on  the  front  of  a  plain  pulley  by  two  clamping  screws. 
The  height  of  the  guide  pulley  e,  and  the  spring/,  are  of  course 
required  to  be  adjusted  to  the  level  of  the  polisher. 

With  this  arrangement  of  apparatus,  Mr.  Hodgson  succeeded 
without  material  difficulty  in  grinding  and  polishing  specula,  one 
of  which  is  3£  inches  aperture,  with  a  focal  length  of  33  inches ; 
this  has  a  tolerably  good  figure,  and  performs  very  well. 


1295 


MACHINE    FOR    GRINDING    SPHERICAL    STOPPERS. 


In  figuring  this  speculum  an  elliptical  polisher  was  used,  the 
proportions  of  which  were  the  same  as  those  recommended  by 
Mr.  Edwards  (see  page  1278).  To  allow  of  the  free  rotation  of 
the  polisher,  which  was  made  of  a  mixture  of  lead  and  tin,  the 
upper  part  was  finished  as  a  cylinder,  to  fit  loosely  in  the  ring, 
and  the  length  of  traverse  of  the  center  of  the  polisher  across 
that  of  the  speculum,  was  rather  more  than  one  inch. 

Mr.  Hodgson  suggests  that  should  it  be  considered  desirable, 
a  second  guide  pulley  may  be  placed  at  the  back,  instead  of  the 
steel  spring,  and  a  second  eccentric  on  the  spindle  of  the  over- 
head motion  would,  no  doubt,  answer  quite  as  well  to  produce 
the  back  stroke ;  but  the  plan  which  he  followed  appeared  in 
his  own  case  to  be  more  easily  executed. 


A  machine  employed  at  the  Vauxhall  pottery  works,  for 
grinding  the  spherical  stoppers  of  air-tight  earthenware  jars,  is 
represented  in  the  diagram,  fig.  1138.  The  stoppers  and  jars 


FIG.  1138. 


n 


were  ground  together  in  the  state  in  which  they  left  the  kiln, 
without  separate  preparation.  About  a  dozen  jars  were  fixed 
by  clamping  apparatus  around  the  margin  of  a  circular  table, 


GLASS-CUTTING.  1296 

that  was  suspended  by  swing  chains  from  the  upper  part  of  the 
frame  of  the  machine.  The  circular  table  was  swung  bodily  in 
a  circle  of  about  three  inches  diameter,  by  a  slowly  revolving 
eccentric  placed  beneath,  and  every  stopper  was  made  to  revolve 
with  considerable  rapidity  within  the  spherical  fitting  of  the  jar 
by  the  following  arrangement. 

A  large  toothed  wheel  fixed  horizontally  in  the  center  of  the 
upper  part  of  the  frame,  communicated  by  a  pair  of  bevil  wheels 
with  a  horizontal  shaft  driven  by  a  strap  from  the  engine. 
Around  the  central  wheel  about  a  dozen  small  pinions  were 
mounted  in  separate  bearings  at  equal  distances,  so  as  to  be  all 
driven  at  the  same  time  by  the  central  wheel.  The  axis  of  every 
pinion  passed  through  its  bearing,  and  terminated  beneath  in  an 
eye  to  which  a  hooked  rod  was  suspended.  To  allow  of  variation 
in  the  length,  this  rod  was  fitted  within  a  piece  of  gas-tube  with 
a  slit  down  the  side  for  a  pin  to  ensure  the  rotation  of  the  tube, 
which  terminated  at  its  lower  extremity  in  a  chuck  for  the 
attachment  of  the  stopper. 

The  rapid  revolution  of  the  stoppers  gave  the  grinding  motion, 
and  the  slow  circular  swinging  of  the  table  derived  from  the 
eccentric  beneath,  gave  the  continual  change  of  position  required 
for  the  true  spherical  form.  The  weight  of  the  tube  and  chuck 
supplied  the  pressure  for  the  grinding,  which  was  begun  with 
sand  and  water,  and  completed  with  emery,  the  time  occupied 
in  grinding  a  dozen  jars  being  about  one  hour.  This  machine 
was  perfectly  successful  in  producing  the  true  spherical  fitting, 
but  is  now  little  used,  as  it  is  found  more  economical  to  grind 
the  stoppers  and  jars  together  in  the  lathe  by  hand,  the  true 
spherical  form  not  being  considered  by  manufacturers  of  sufficient 
importance  to  justify  the  additional  expense  of  the  machine. 

SECT.  V. GLASS-CUTTING. 

GLASS  cutting,  or  the  grinding  and  polishing  of  cut  glass  for 
household  and  other  purposes,  is  effected  with  revolving  wheels 
of  iron,  stone,  or  wood,  mounted  on  horizontal  spindles,  after  the 
same  general  method  as  the  grindstones  and  buff-wheels  of  the 
cutler ;  but  the  grinding  of  glass  requires  a  plentiful  supply  of 
water,  which  mostly  runs  in  a  small  stream,  from  either  a  hopper- 
shaped  box,  or  a  can,  placed  above  the  revolving  wheel;  the 


1297 


GLASS-CUTTER  S    WHEEL. 


water  is  led  by  a  sloping  channel  to  the  upper  edge  of  the  wheel, 
and  a  small  piece  of  wood  is  placed  nearly  upright  and  in  con- 
tact with  the  wheel,  a  little  in  advance  of  the  point  at  which  the 
water  is  delivered,  in  order  to  distribute  it  equally  over  the 
edge.  A  splash-board  is  fixed  behind  the  wheel,  to  catch  the 
water  thrown  off,  by  centrifugal  force,  and  lead  it  to  the  trough 
placed  beneath;  a  second  splash-board  is  sometimes  fixed  in 
front,  to  protect  the  operator  from  the  wet. 

Figs.  1139  and  1140  represent,  in  two  views,   the  general 
arrangement  of  the  apparatus  employed  in  large  manufactories, 


FIG.  1139. 


cv n 

\       1 


FIG.  11 40. 


where  the  spindles  are  usually  driven  by  steam  power,  but  in 
small  workshops,  and  for  occasional  purposes,  the  foot- wheel  and 
treadle  are  employed,  in  much  the  same  manner  as  in  the  small 
grinding  machine  shown  in  fig.  1030,  except  that  the  spindles 
are  placed  a  few  inches  higher. 

The  wheels,  whether  of  iron,  stone,  or  wood,  are  generally 
made  from  about  6  to  20  inches  diameter,  and  about  1  to  1| 
in  thickness  ;  a  considerable  variety  is  required  of  all  the  three 
kinds,  with  flat,  angular,  rounded,  or  concave  edges,  to  suit  the 
different  forms  in  which  the  glass  is  to  be  cut ;  the  wheels  are 


ROUGHING    CUT    GLASS.  1298 

mounted  upon  separate  spindles,  and  are  exchanged  in  exactly 
the  same  manner  as  those  used  by  cutlers. 

The  majority  of  the  hollow  works  in  cut  glass,  such  as  wine 
glasses  and  decanters,  are  blown  to  the  circular  form,  and  the 
ornament  is  entirely  produced  by  grinding  and  polishing ;  some 
few  of  the  hollow  works  are  blown  in  figured  moulds,  and  the 
general  forms  thus  produced  are  finished  by  cutting.  Small  solid 
objects,  such  as  the  prisms  and  drops  for  chandeliers,  are  mostly 
pinched,  or  the  glass,  while  red  hot,  is  pressed  into  the  cavities 
of  metal  moulds,  something  like  those  for  casting  bullets,  but 
formed  with  the  required  facets ;  and  for  chandelier  drops  the 
moulds  are  provided  with  steel  wires,  that  pierce  the  apertures 
for  the  brass  wires,  by  which  the  glass  drops  are  united  to  form 
the  chandelier. 

The  first  process  in  glass-cutting,  or  the  rough  grinding,  is 
performed  with  cast-iron  wheels,  called  mills,  turned  truly  cir- 
cular, and  of  the  required  figure,  on  their  own  spindles;  the 
mills  are  supplied  with  fine  sand,  that  has  been  previously  washed 
and  sifted,  to  free  it  from  dirt,  or  coarse  particles  of  grit. 
The  sand  is  placed  in  the  hopper,  which  is  filled  up  with  water, 
and  the  opening  at  the  bottom  adjusted  by  a  plug,  so  as  to  allow 
a  stream  of  the  mixed  sand  and  water,  of  about  one  quarter  of 
an  inch  diameter,  to  flow  through. 

The  glass  to  be  ground  is  applied  either  above  or  below  the 
center  of  the  mill,  according  to  the  convenience  of  the  operator. 
If  the  object  be  large,  and  much  has  to  be  ground  away,  the 
work  is  generally  applied  above  the  center,  as  this  position  is 
less  fatiguing  for  the  arms;  and  hollow  objects  are  in  general 
sufficiently  transparent  to  allow  of  the  operator  looking  through 
the  article  to  see  the  progress  of  the  work.  Small  solid  objects, 
and  such  as  are  not  transparent,  are  mostly  applied  below  the 
center,  to  enable  the  workman  to  watch  the  progress  of  the  cut- 
ting ;  in  this  case  a  wooden  bar  is  laid  across  the  water  trough, 
upon  which  the  arms  are  rested,  partly  to  avoid  fatigue,  and 
partly  to  give  greater  steadiness. 

When  the  object  to  be  ground  is  large,  and  is  required  to 
have  several  faces,  or  flutes,  the  circumference  is  divided  with  a 
pair  of  compasses  into  the  required  number  of  parts  for  the  prin- 
cipal circle,  and  the  divisions  are  roughly  scratched  with  an  old 
triangular  file,  ground  like  a  triangular  turning  tool ;  the  height 

VOL,  m.  T 


1299  SMOOTHING    CUT    GLASS. 

of  the  flutes  is  also  marked  on  the  best  works.  These  divisions 
assist  the  workman  in  cutting  the  first  circle  of  flutes  of  uniform 
size,  and  which  serves  as  the  basis  for  all  the  other  circles  of 
flutes,  which  are  mostly  placed  intermediate  with  the  adjacent 
circle,  and  are  successively  produced  under  the  guidance  of  the 
eye  alone.  Small  articles,  such  as  wine-glasses,  are  not  generally 
divided  with  the  compasses,  unless  for  the  best  works,  as,  from 
constant  habit,  the  glass-cutters  attain  considerable  dexterity  in 
grinding  any  regular  number  of  faces  upon  a  circular  object. 

Generally  the  edge  of  the  mill  is  alone  employed  for  cutting, 
and  the  faces  produced,  therefore,  partake  of  the  curvature  of 
the  mill,  and  are  ground  concave  instead  of  flat,  and  which  has 
the  advantage  of  making  the  intersections  of  the  edges  appear 
sharper ;  when,  however,  the  surfaces  are  required  to  be  quite 
flat,  the  side  of  the  mill  is  employed  in  the  same  manner  as  for 
lapping  the  metals. 

For  cutting  long  straight  faces,  the  work  is  held  parallel  with 
the  axis  of  the  mill,  and  gradually  traversed  from  end  to  end, 
over  a  flat-edged  mill.  For  curved  surfaces,  such  as  the  neck  of 
a  claret  jug,  a  mill  with  a  slightly  rounded  edge  is  used,  and  the 
work  is  traversed  in  a  curved  path.  For  angular  grooves,  or 
splits,  up  the  side  of  a  decanter,  or  similar  object,  a  mill  with  an 
angular  edge  is  employed,  and  the  decanter  is  held  upright,  or 
at  right  angles,  to  the  axis  of  the  mill,  the  same  position  is  also 
employed  for  convex  ribs,  called  pillars,  for  which  a  concave  mill 
is  used.  In  rough  grinding,  the  work  is  applied  with  considerable 
pressure,  and  large  deeply-cut  flutes  sometimes  require  as  much 
as  one  horse  power  to  drive  the  mill.  When  the  supply  of  water 
in  the  hopper  is  exhausted,  it  is  ladled  back  from  the  trough,  the 
same  supply  of  water  serving  for  several  days'  use,  or  until  it 
becomes  dirty. 

The  second  process  in  glass-cutting  is  the  smooth  grinding  of 
the  flutes ;  this  is  done  upon  fine  grit-stones,  known  either  as 
York  or  Warrington  stones.  These  varieties  of  grit-stones  are 
chosen  because  they  are  fine  and  compact  in  the  grain,  and  are 
capable  of  retaining  sharp  angular  edges.  The  York  stones  are 
the  harder,  and  are  usually  selected  from  the  finest  grained 
pieces  of  Yorkshire  paving  slabs. 

The  'stones  are  ground  very  true  to  the  circular  form,  by 
means  of  a  stationary  bar  of  iron  supported  on.  the  water  trough, 


POLISHING    CUT    GLASS.  1300 

and  supplied  with  sand  and  water;  the  stones  are  afterwards 
smoothed — first,  with  a  piece  of  stone  of  the  same  quality,  held 
in  the  hand  ;  and,  lastly,  with  a  piece  of  flint,  similarly  applied  : 
this  leaves  the  surfaces  of  the  stones  quite  smooth,  and  almost 
polished.  If  the  stones  were  left  with  a  rough  surface,  the  glass 
would  not  hang  to  the  stones,  but  would  slip  away,  and  be  quite 
unmanageable.  A  smaller  stream  of  water  is  required  with  the 
stones  than  with  the  cast-iron  mill,  and  a  straw  frequently  serves 
as  the  channel  for  leading  the  water  from  the  can  to  the  stone. 
•  A  piece  of  sponge  is  often  attached  to  the  sloping  board  s, 
in  front  of  the  straw,  to  moisten  the  stone  uniformly,  as  the 
stone  must  be  kept  tolerably  wet,  or  it  will  generate  so  much 
heat  as  to  break  the  glass. 

More  care  is  required  in  the  smoothing  than  in  the  roughing, 
as  the  smooth  grinding  gives  the  finished  form  to  the  glass,  and 
at  the  same  time  a  very  smooth  surface.  If  the  smoothing  is 
carried  on  too  vigorously,  the  stone  is  liable  to  jar  the  glass  or 
put  it  in  vibration,  this  causes  the  glass  to  squeak,  or  make  a 
noise  like  a  dry  cart  wheel,  and  frequently  the  glass  breaks 
immediately  afterwards,  unless  it  be  applied  to  the  stone  with 
reduced  pressure,  and  also  more  firmly  held  in  order  to  prevent 
the  glass  from  vibrating.  In  smoothing  the  slender  neck  of  a 
bottle,  a  cork  is  sometimes  inserted  to  check  the  vibration, 
which  never  occurs  in  the  rough  grinding  with  loose  sand,  and  is 
less  frequent  in  smoothing  with  Warrington  stones  than  with 
the  harder  York  stones. 

The  work  is  applied  to  the  stone  for  smoothing  in  exactly  the 
same  manner  as  upon  the  mill  for  roughing,  but  the  work  is 
more  frequently  held  below  the  center  of  the  stone,  and  in 
finishing  straight  flutes  they  are  often  applied  upright,  or  at 
right  angles  to  the  axis  of  the  stone,  as  in  this  position  they 
may  be  made  somewhat  straighter,  and  smoothed  rather  more 
expeditiously.  The  stones  used  for  this  purpose  are  sometimes 
as  much  as  three  inches  in  thickness. 

After  the  smooth  grinding  the  glass  is  polished  on  wheels  of 
willow,  cut  transversely  out  of  round  timber,  and  turned  true 
and  smooth.  The  wooden  wheels  are  charged  with  pumice  stone 
powder,  mixed  with  water,  and  applied  with  a  brush ;  some- 
times rotten  stone  is  mixed  with  the  pumice  stone.  As  in  the 
cutting  process  the  edges  of  the  wheels  are  principally  used,  but 

T2 


1301  FITTING    STOPPERS    INTO    GLASS    BOTTLES,  ETC. 

the  work  is  almost  always  applied  on  the  top  of  the  wheel,  when 
the  latter  are  driven  by  power,  and  instead  of  the  glass  being 
held  in  one  position  and  traversed  endways,  it  is  twisted  about 
in  all  directions,  to  remove  the  marks  made  by  the  stone  in 
smoothing.  The  final  lustre  is  given  with  wet  putty  powder 
applied  also  on  willow  wheels. 

Wheel  brushes  of  about  8  or  10  inches  diameter,  supplied 
with  pumice  stone,  rotten  stone,  or  putty  powder,  are  also  used 
as  an  expeditious  means  of  polishing  those  parts  of  cut  glass  in 
which  the  sharpness  of  the  angles  is  not  considered  to  be  of  • 
great  importance,  but  the  use  of  the  wheel  brushes  is  avoided  as 
much  as  possible  in  polishing  the  best  works. 

In  fitting  the  conical  stoppers  into  glass  bottles,  the  hollow 
cone  of  the  bottle  is  ground  by  means  of  a  solid  cone  of  iron, 
sometimes  roughened  like  a  steel  for  sharpening  knives.  The 
cone  is  chucked  on  a  lathe  mandrel,  and  fed  with  emery  and 
water.  The  stoppers  are  fixed  in  a  hollow  wood  chuck  by  slight 
blows  of  a  mallet,  and  are  ground  also  with  emery  and  water, 
applied  on  a  grinder  made  of  a  piece  of  sheet  iron,  hammered 
ground  a  cone  of  the  same  angle,  and  left  with  two  flaps  or  ears, 
by  which  the  grinder  is  held  and  compressed  upon  the  revolving 
glass  stopper. 

The  cones  are  ground  separately  until  the  stopper  will  enter 
the  bottle,  to  within  about  one-sixteenth  of  an  inch  of  the 
intended  position,  the  two  are  then  slightly  ground  together  for 
the  exact  fitting.  The  stoppers  of  the  best  works  are  afterwards 
polished  on  the  edge  of  the  willow  wheels,  in  the  same  manner 
as  cut  glass.  The  internal  cone  is  polished  on  a  small  willow 
cone  revolving  in  the  lathe. 

The  large  stoppers  for  medical  bottles  are  sometimes  rough 
ground  with  sand,  on  the  flat  side  of  a  mill  made  of  stout  sheet  iron, 
and  which  also  serves  for  grinding  the  bottom  of  the  bottle  flat. 

Glass  drops  for  chandeliers  are  cut  upon  the  flat  faces  of 
wheels,  which  sometimes  revolve  horizontally,  and  are  almost 
entirely  concealed  within  wooden  cases  to  catch  the  dirt,  only  a 
small  opening  being  left  for  applying  the  drops.  They  are 
roughed  with  sand  and  water  on  iron  mills,  smoothed  on  stones, 
and  polished  on  lead  laps  supplied  with  rotten  stone  and  water 
the  lead  is  considered  to  produce  a  black  polish  that  reflects  tl 
prismatic  colours  in  a  higher  degree  than  when  wood  is  employed 
as  the  material  for  the  polisher* 


CHAPTER  XXXIV. 

LAPIDARY  WORK. 


SECT.  I.  —  SLITTING,     CUTTING,    AND     POLISHING    FLAT    AND     ROUNDED 

WORKS. 

ALTHOUGH  the  term  lapidary  work,  may  seem  to  be  applicable 
to  all  the  various  modes  of  working  or  finishing  stones,  it  is 
restricted  to  the  cutting,  grinding,  and  polishing  of  gems  and 
small  stones,  and  some  other  materials,  principally  for  jewellery, 
or  mineralogical  specimens. 

The  lapidary  never  employs  abrasive  materials  in  that  which 
may  be  called  their  natural  or  unprepared  state,  in  the  manner 
that  the  grindstone  or  oilstone  are  employed  for  restoring  the 
edges  of  tools ;  but  he  uses  the  several  abrasive  materials  in  a 
pulverized  form,  and  upon  revolving  disks  of  metal  and  other 
materials  by  way  of  vehicles,  thus  constituting  artificial  grinders, 
which  he  denominates  as  mills;  thus  we  have  the  slitting  mill, 
the  roughing  mill,  the  smoothing  mill,  and  the  polishing  mill,  all 
generally  of  metal ;  but  for  soft  stones  the  smoothing  mill  is  some- 
times a  plain  disk  of  willow  wood  or  mahogany.  The  polishing 
mill  is  sometimes  composed  of  a  spiral  coil  of  list  placed  on  edge 
like  the  leaves  of  a  book  ;  sometimes  of  bristles  like  a  brush,  or 
of  wood  covered  with  buff  leather,  which  several  apparatus  are 
fully  described  under  the  head  WHEELS,  in  the  Catalogue  of 
Abrasive  Processes  at  the* commencement  of  this  volume. 

The  general  succession  in  which  these  mills  are  employed  by 
the  lapidary  for  substances  of  different  degrees  of  hardness,  is 
also  briefly  explained  in  the  catalogue  under  the  three  heads, 
ALABASTER,  CARNELIAN,  and  SAPPHIRE,  stones  that  differ  consider- 
ably in  hardness,  and  have  therefore  been  selected  as  general 
examples ;  under  each  head  is  appended  a  list  of  such  gems  and 
other  substances  as  are  worked  by  the  lapidary  in  a  similar 


1303  GENERAL    REMARKS    ON    LAPIDARY    APPARATUS. 

manner.  The  principal  peculiarities  in  the  methods  of  working 
other  stones,  are  also  mentioned  in  the  catalogue  under  their 
respective  names,  as  Agate,  Amber,  Avanturine,  &c. 

The  general  remarks  offered  under  these  heads,  have  greatly 
abridged  the  observations  to  be  submitted  in  the  present  chapter, 
which  will  be  confined  principally  to  a  description  of  the  appa- 
ratus, and  the  details  of  manipulation,  which  are  nearly  alike  in 
working  corresponding  forms  in  either  hard  or  soft  stones ;  the 
principal  difference  being  that  the  polishing  mills  are  composed 
of  hard  or  soft  materials,  according  to  the  degree  of  hardness  of 
the  substances  to  be  polished. 

The  apparatus  commonly  employed  by  the  practical  lapidary 
will  be  first  described,  followed  by  some  account  of  the  methods 
of  producing  the  more  usual  forms  met  with  in  lapidary  work, 
and  the  modifications  in  the  apparatus  generally  employed  by 
amateurs  for  similar  purposes  will  be  subsequently  adverted  to. 


All  the  mills  of  the  lapidary  revolve  upon  vertical  spindles  or 
axes,  so  that  the  disks  travel  horizontally,  which  is  just  the 
reverse  of  the  position  employed  by  the  cutler,  and  also  by  the 
glass  and  gold  cutters,  although  the  two  latter  classes  of  artizans 
are  in  the  frequent  habit  of  working  analogous  forms,  and  in 
some  few  instances,  as  in  the  case  of  cutting  facets  on  amber 
beads,  the  gold  cutters  are  considered  to  excel  the  ordinary 
lapidary. 

Flat  and  rectilinear  works  are,  in  all  their  stages,  ground  and 
polished  upon  the  broad  flat  surfaces  of  the  lapidary  mills,  which 
revolve  with  moderate  velocity,  and  the  work  is  held  almost 
stationary,  much  the  same  as  in  lapping  flat  works  in  metal. 

Convex  works  are  roughened  on  the  ordinary  flat  roughing 
mill ;  but  they  require  to  be  continually  rolled  about  to  bring 
every  part  in  quick  succession  into  contact  with  the  mill  or  disk, 
as  holding  the  stone  at  rest  would  inevitably  wear  down  a  flat 
place.  Convex  works  in  soft  substances  are  in  general  smoothed 
on  a  wooden  disk,  which,  from  its  elasticity,  and  also  from  its 
surface  wearing  slightly  rough,  or  fibrous,  yields  a  little  to  the 
stone,  and  does  not  meet  it  so  rigidly  upon  one  mathematical 
line  as  the  unyielding  metal  disk.  The  list  mill,  from  its  pliancy, 


GENERAL    REMARKS    ON    LAPIDARY    APPARATUS.  1304 

is  also  very  well  adapted  to  convex  works,  and  is  commonly  used 
for  glass ;    the  leather  and  brush  mills  are   also   occasionally 
mployed  for  rounded  works. 

Concave  works  necessarily  require  mills  that  will  penetrate 
nto  their  cavities ;  the  rounded  edge  of  the  disk  is  in  this  case 
sed  somewhat  as  a  glass-cutter  would  grind  a  transverse  flute, 
xcept  that  the  work  is  held  at  an  angle  instead  of  parallel  to 
he  axis.     But  when  the  cavity  is  required  to  be  spherical,  or 
rvilinear  in  two  directions,  the  grinder  is  required  to  be  of  a 
ulbous  form,  and  of  the  suitable  diameter   for  the  required 
rvatures,  and  the  grinding  and   polishing  tools  must  be  all 
urned  to  the  same  diameter. 

In  Germany  and  other  parts  of  the  Continent,  where  large 
uantities  of  common  lapidary  works,  such  as  seal  handles,  are 
xecuted,  water-power  is  generally  employed  for  driving  the 
ills,  which  for  these  works  are,  in  some  cases,  mounted  upon 
rizontal  spindles,  and  the  edges  of  the  mills  are  then  principally 
used.  The  cutting  of  diamonds  has  been  slightly  noticed  in 
vol.  i.,  page  176 ;  as  there  mentioned,  the  facets  are  cut  by 
cementing  two  diamonds  upon  the  ends  of  two  sticks,  and  rub- 
bing them  together.  The  facets  are  afterwards  polished  upon 
an  iron  skive  or  mill,  charged  with  diamond  powder ;  consider- 
able pressure  is  exerted  upon  the  stone,  and  in  Holland,  where 
the  greatest  quantity  of  diamonds  are  cut  and  polished,  horse 
power  is  generally  employed,  or  the  mills  are  driven  by  one  or 
two  men.  In  the  latter  case  the  driving-wheel  is  about  6  feet 
diameter,  and  instead  of  being  mounted  vertically,  and  driven 
by  a  winch  handle,  as  usual  in  this  country  for  similar  pur- 
poses, the  driving  wheel  is  mounted  to  revolve  horizontally, 
upon  a  vertical  spindle,  having  a  crank  of  small  radius,  to 
which  the  motion  is  communicated  by  a  connecting  rod  lead- 
ing to  a  wooden  frame,  that  swings  horizontally  upon  pivots  at 
the  one  end,  like  an  ordinary  gate,  and  has  at  the  other  end 
two  upright  handles,  by  which  it  is  pushed  alternately  back- 
wards and  forwards. 

The  stones  worked  in  this  country  by  lapidaries  are  in  general 
email,  and  but  little  pressure  is  exerted  upon  the  stone,  the  power 
of  an  assistant  is  therefore  not  required  ;  but  the  lapidary  mostly 
gives  motion  to  the  wheel  with  his  left  hand,  while  the  stone  is 
applied  to  the  mill  with  his  right.  The  details  of  the  apparatus 

! 


1305 


LAPIDARY  S    BENCH. 


are  somewhat  varied  in  unimportant  particulars,  but  fig.  1141 
may  be  considered  to  represent  the  general  arrangement  of 
apparatus  employed  by  working  lapidaries. 

The  lapidary's  bench  consists  of  a  stout  plank,  about  3  feet  6 
inches  long,  and  1  foot  9  inches  wide,  supported  upon  a  frame  about 


FIG.  1141. 


2  feet  6  inches  high ;  the  top  is  divided  into  two  unequal  com- 
partments, and  the  whole  is  surrounded  by  a  rim  of  about  2  inches 
above  the  face  of  the  bench,  intended  to  catch  the  waste  emery 
and  water  thrown  off  by  the  centrifugal  force.  The  compai 
ment  to  the  left  hand  is  about  2  feet  long,  and  has  a  cent] 
hole  fitted  with  a  collar,  through  which  passes  the  vertic 
spindle  of  the  driving  wheel  a,  the  lower  end  of  the  spindle  is 
made  conical,  and  fits  into  a  corresponding  center  #,  fixed  in  the 
longitudinal  rail  of  the  frame.  The  driving  wheel,  about  18 
inches  diameter,  is  fitted  on  the  spindle  between  flanges,  am 


' 


LAPIDARY'S  BENCH.  1306 

works  just  beneath  the  under  surface  of  the  bench  top,  which 
nearly  conceals  it,  and  a  horizontal  handle  c,  of  about  6  inches 
radius,  is  fitted  on  the  upper  end  of  the  spindle.  The  distance 
between  the  spindle  of  the  driving  wheel,  and  that  of  the  lap  or 
mill,  should  not  exceed  about  1  foot  9  inches,  in  order  that  the 
arms  may  not  be  inconveniently  extended,  when  the  hands  are 
respectively  applied  to  the  wheel  and  mill. 

The  right  hand  compartment  of  the  bench  is  about  16 
inches  wide,  and  through  a  hole  in  the  center  is  passed  the 
spindle  d,  that  carries  the  mill ;  this  latter  is  usually  about  8 
or  9  inches  diameter,  and  revolves  about  1  inch  above  the 
surface  of  the  bench.  The  spindle  is  about  18  inches  long,  and 
the  mill  is  held  between  a  flange  and  screwed  nut,  about  12  inches 
from  the  lower  end,  which  is  made  conical,  and  received  in  a 
corresponding  center,  capable  of  adjustment  for  height,  in  order 
to  compensate  for  irregularities  in  the  lengths  of  the  spindles, 
and  also  to  allow  of  the  mill  being  more  or  less  elevated  above 
the  face  of  the  bench,  according  as  the  edge  or  side  of  the  mill 
may  be  employed  at  the  time.  In  the  bench  represented  in  the 
figure,  this  center  consists  of  a  square  wooden  rod,  passing 
through  a  mortise  in  the  transverse  rail  of  the  frame,  and 
retained  at  any  desired  height  by  a  side  wedge  ;  but  frequently 
the  center  is  supported  upon  the  middle  of  a  transverse  bar 
moving  at  the  one  end  on  a  pivot  in  the  back  upright  of  the  frame, 
and  supported  in  the  front  by  a  wedge. 

The  upper  end  of  the  spindle  is  also  made  conical,  and  likewise 

rks  in  a  wooden  center,  which  is  screwed  into  a  hole  near  the 
xtremity  of  a  horizontal  iron  arm  e,  that  slides  upon  a  perpen- 
dicular bar  /,  fixed  behind  the  mill ;  the  height  of  the  horizontal 
bar  is  adjusted  to  suit  the  height  of  the  spindle,  and  is  retained 
in  the  proper  position  by  the  binding  screw  g.  The  pulley,  about 
four  inches  diameter,  is  fixed  on  the  spindle  to  work  just  below 
the  bench  top,  the  hole  through  which  is  sufficiently  large  to 
allow  the  pulley  to  be  passed  through,  either  in  exchanging  the 
ills,  or  when  they  are  required  to  be  elevated. 

The  support  shown  at  h,  placed  a  little  to  the  right  and  in 
advance  of  the  lap,  is  called  a  gim  peg  or  germ  peg ;  it  is  about 
8  inches  high,  and  made  of  a  round  rod  of  iron  bent  into  a 
crank  form,  and  fitted  with  a  flange  that  bears  upon  the  surface 
of  the  bench  ;  the  lower  end  of  the  rod  passes  through  a  hole  or 


I 


1307 

mortise  in  the  bench,  and  is  fixed  by  a  wing  nut  beneath,  in 
order  to  allow  of  the  gim  peg  being  twisted  round  to  different 
positions,  according  to  the  distance  it  is  required  to  be  placed 
from  the  mill. 

The  gim  peg  serves  as  a  support  for  the  arm  of  the  workman 
in  grinding  the  edges  of  small  stones,  but  its  principal  use  is  to 
serve  as  a  guide  for  the  vertical  angle  in  cutting  facets ;  for  this 
purpose  a  wooden  socket,  of  the  form  shown  in  the  figure,  is 
slipped  over  the  upper  part  of  the  rod,  and  retained  in  its 
position  by  a  wedge  driven  in  between  the  iron  stem  and  the 
hole  in  the  wooden  socket.  Several  series  of  holes,  or  rather 
notches,  one  above  the  other,  are  arranged  around  the  sides  of 
the  socket,  and  which  serve  to  determine  the  inclination  of  the 
stick  upon  which  the  stones  are  cemented,  as  will  be  hereafter 
explained. 

In  producing  a  plane  surface  upon  an  irregular  piece  of  stone, 
as  in  the  case  of  smoothing  a  mineralogical  specimen,  if  the 
natural  surface  is  so  nearly  flat  that  but  little  has  to  be  removed, 
the  stone  may  be  at  once  applied  to  the  flat  surface  of  the 
roughing  mill;  and  if  the  stone  be  soft,  such  as  a  piece  of 
potstone,  the  flat  surface  will  be  quickly  attained ;  but  if  the 
natural  surface  be  irregular,  and  the  stone  be  hard,  such  as  a 
piece  of  bloodstone,  or  even  an  ordinary  pebble,  the  reduction  of 
the  stone  to  a  flat  surface  by  grinding  would  be  very  tedious,  if 
much  of  the  material  had  to  be  removed.  Splitting  or  cleavage 
is  seldom  resorted  to,  as  few  of  the  stones  wrought  by  the 
lapidary  have  a  sufficiently  lamellar  structure  to  allow  of  nearly 
plane  surfaces  being  thus  produced,  and  the  surfaces  would  be 
also  liable  to  interferences  from  flaws  or  veins  in  the  stone.  In 
the  majority  of  cases,  therefore,  even  in  polishing  mineralogical 
specimens,  the  level  surface  is  produced  by  cutting  off  a  thin  slice 
of  the  stone  with  the  slitting-mill  or  slicer,  which  is  a  revolving 
disk  of  thin  sheet  iron,  charged  on  the  edge  with  diamond 
powder,  and  used  as  a  circular  saw  for  dividing  all  stones  inferior 
in  hardness  to  the  diamond. 

Notwithstanding  the  apparent  expence  of  the  diamond  powder, 
it  is  very  generally  employed,  and  is  used  for  cutting  nearly  every 
Turkey  oilstone  that  is  sold  ;  and  although  for  this  and  some  of 
the  softer  stones,  emery,  or  in  some  cases  even  sand,  might  be 
successfully  employed,  the  diamond  powder  is  almost  exclusively 


LAPIDARY'S  SLITTING  MILL.  1308 

used,  as  it  is  found  to  be  the  most  economical,  when  the  time 
occupied  in  the  cutting  is  taken  into  account.  The  diamond 
powder  cuts  more  rapidly  than  emery,  and  is  very  much  more 
enduring ;  it  also  admits  of  being  employed  with  very  thin 
plates,  and  consequently  the  progress  is  also  more  expeditious  on 
this  account,  and  comparatively  only  a  small  thickness  of  mate- 
rial is  wasted  in  the  cutting.  This  is  sometimes  an  important 
object  with  valuable  stones,  and  the  slicer  is  then  made  of  small 
diameter,  in  order  that  it  may  be  as  thin  as  possible,  and  still 
retain  the  required  degree  of  stiffness. 

The  slicer  is  made  of  a  disk  of  sheet  iron,  usually  about  eight 
or  nine  inches  diameter,  and  two  hundredths  of  an  inch  in  thick- 
ness. It  is  of  course  necessary  that  the  edge  of  the  slicer 
should  run  exactly  in  one  plane ;  it  is  therefore  planished  or 
hammered  in  the  manner  explained  in  vol.  i.,  pp.  414  to  422. 
But  if  so  thin  a  plate  were  made  perfectly  flat,  like  a  circular 
saw,  it  would  be  very  feeble  sideways,  and  would  be  readily 
distorted  by  the  resistance  of  the  work,  and  therefore,  to  give 
greater  rigidity,  the  slicer  is  hammered  into  a  slightly  arched 
or  dished  form,  the  concavity  being  about  one-sixth  of  an  inch  in 
the  entire  diameter.  This  trifling  concavity  materially  increases 
the  stiffness  of  the  slicer,  and  does  not  interfere  with  its  use  for 
cutting  straight  sections;  as  when  the  slicer  is  properly  ham- 
mered and  turned  true,  the  extreme  edge  runs  exactly  in  one 
plane  for  the  commencement  of  the  cut ;  and  when  the  slicer 
has  penetrated  a  small  depth,  the  trifling  curvature  of  the  plate 
gives  way,  and  it  is  flattened  by  the  groove  it  has  itself  cut,  and 
in  which  it  is  compelled  to  run. 

The  slicer  is  further  stiffened  by  being  firmly  clamped,  like  a 
circular  saw,  between  two  flanges  on  its  spindle,  which  is  made  of 
such  a  length  that  the  edge  of  the  slicer  may  be  about  3  inches 
above  the  level  of  the  bench,  in  order  to  allow  room  for  the  hand, 
and  also  for  large  stones. 

The  preparation  of  the  diamond  powder  for  charging  the 
slicer  has  been  already  described  on  page  1052,  under  the  head 
DIAMOND,  Article  1 ;  but  it  may  be  added  that  the  usual  criterion 
for  the  fineness  of  the  diamond  powder  used  by  lapidaries,  is 
that  the  particles  should  be  so  small  that  no  sparkling  is  per- 
ceptible when  the  diamond  powder  is  exposed  to  the  light. 
Slight  differences  are  made  in  the  forms  of  mortars  for  crushing 


1309    MORTARS    FOR  CRUSHING  AND    GRINDING  DIAMOND    POWDER. 


diamonds,  but  that  represented  in  fig.  1142  is  the  more  gene- 
rally preferred.     The   mortar  «,  has  a   deep  cylindrical  hole 


FIGS.  1142. 


1143. 


1144. 


terminating  at  the  bottom  in  a  spherical  cavity  of  hardened 
steel,  embracing  from  about  one-third  to  one-sixth  of  a  circle, 
into  which  the  pestle  b,  is  accurately  fitted  by  grinding.  The 
long  cylindrical  fitting  serves  as  a  guide  for  keeping  the  pestle 
upright,  and  also  prevents  any  of  the  valuable  particles  from 
flying  about  when  the  pestle  is  struck  with  the  hammer ;  the 
cover  c,  is  also  added  for  the  latter  purpose.  In  some  mortars 
for  crushing  diamonds,  the  bottom  of  the  cavity  is  made  flat, 
and  the  pestle  is  then  made  square  at  the  end,  as  shown  in 
fig.  1 143,  in  which  a  represents  the  base  of  the  mortar,  b,  a  short 
cylindrical  tube  fitted  into  a  shallow  cavity  in  the  base,  and  c, 
the  pestle,  which  is  fitted  within  the  tube.  But  this  form  of 
mortar  is  seldom  employed  by  working  lapidaries. 

Sometimes,  when  the  diamond  has  not  been  crushed  suffi- 
ciently fine  in  the  mortar,  the  lapidaries  grind  the  diamond 
powder ;  for  this  purpose  they  commonly  mix  it  with  a  little 
olive  oil  or  the  oil  of  brick,  and  spread  it  upon  a  flat  piece  of 
iron,  generally  an  old  laundry  iron,  and  any  small  piece  of  iron 
is  used  as  a  muller.  The  mortar  represented  in  fig.  1144  is, 
however,  greatly  preferable  for  grinding  the  diamond  powder. 
The  base  a  of  the  mortar  has  a  spherical  cavity,  of  hardened 
steel  and  about  two  inches  radius,  to  which  is  fitted  the  pestle  3, 
which  is  also  made  of  hardened  steel  and  fixed  in  a  wooden 
handle.  The  diamond  powder  is  placed  in  the  center  of  the 
cavity,  and  a  few  drops  of  oil  are  added ;  the  diamond  is  then 


SEASONING,  OR    CHARGING  THE    SLICER. 


1310 


ground   as  fine  as  required  by  rubbing  the  pestle  within  the 
mortar  with  moderate  pressure. 

In  applying  the  diamond  powder  to  a  new  slicer,  or  as  it  is 

lied  seasoning  the  slicer^  it  is  mounted  in  the  machine,  and  the 
jdge  is  turned  quite  true  and  smooth,  with  a  graver  supported 
ipon  the  rest  /z,  fig.  1141  ;  or  in  some  cases  it  is  afterwards 

loothed  with  a  fine  file,  as  it  is  of  importance  that  the  edge  of 

le  slicer  should  be  quite  true,  and  free  from  even  minute  notches, 
>r  otherwise  the  irregularities  would  be  liable  to  catch  the  stone, 

id  throw  it  out  of  the  hand,  or  if  the  stone  were  firmly  held, 
the  slicer  would  become  distorted. 

A  small  quantity  of  diamond  powder,  mixed  with  the  oil  of 
>rick,  is  then  taken  out  of  the  cup  with  a  small  piece  of  stick,  or 

better  practice  is  to  employ  a  piece  of  an  ordinary  quill  about 

inch  long,  prepared  by  splitting  the  barrel  of  a  quill  length- 
fays  into  three  or  four  pieces,  and  rounding  the  ends.  The 
[uill  is  dipped  in  the  cup,  and  a  little  of  the  diamond  powder,  or 

ither  paste,  is  taken  on  the  concave  side  of  the  quill,  which  is 
then  held  vertically  against  the  edge  of  the  slicer,  so  that  the 

irvature  of  the  slicer  may  nearly  agree  with  that  of  the  quill ; 

le  latter  is  then  held  steady  while  the  slicer  is  moved  slowly 

>und,  in  order  to  distribute  the  diamond  uniformly  on  the 
)xtreme  edge  of  the  slicer.  To  fix  the  particles  therein,  a  smooth 
>iece  of  any  hard  stone,  such  as  agate  or  flint,  from  half  an  inch 
an  inch  wide,  is  immediately  applied  with  gentle  pressure 

jainst  the  edge  of  the  slicer. 

In  order  that  both  hands  may  be  at  liberty  for  charging  the 
licer,  the  wheel  is  sometimes  turned  by  an  assistant,  and  the 

ipidary  supplies  the  diamond  powder  with  one  hand  while  he 

>lds  the  charging  stone  to  the  edge  of  the  slicer  with  the  other. 
is  soon  as  the  diamond  begins  to  cut  the  stone,  the  latter  is 
shifted  to  another  position,  as,  if  the  slicer  were  permitted  to 

it  a  groove  in  the  charging  stone,  the  diamond  powder  would 

jcome  fixed  in  the  sides  of  the  slicer,  which  must  of  course  be 
ivoided.  As  soon  as  the  small  quantity  of  diamond  resting  on 
edge  of  the  slicer  has  been  pressed  into  it,  the  margin  of  the 
slicer  is  carefully  wiped  on  both  sides  with  the  forefinger,  in 
order  to  remove  any  small  portions  of  the  diamond  that  may 
have  become  accidentally  lodged  on  the  sides,  and  these  particles 
are  pushed  to  the  edge  of  the  slicer,  and  pressed  in  with  the 


1311  SLICING    GEMS    AND    STONES. 

charging  stone.  When  the  whole  of  the  diamond  powder  has 
been  pressed  in  to  the  extreme  edge,  a  second  quantity  is 
applied  in  the  same  manner,  and  which  is  generally  sufficient  foi 
charging  or  seasoning  a  new  slicer.  After  the  edge  of  the  slicer 
has  been  once  fairly  charged  with  the  diamond  powder,  a  single 
application  is  generally  sufficient  for  restoring  the  cutting  edge, 
and  under  the  hands  of  the  practical  lapidary,  a  single  seasoning 
will  endure  several  hours1  work. 

The  stone  to  be  sliced  is  first  washed  clean  and  dried,  the  line 
of  the  intended  section  may  then  be  marked  in  ink  as  a  guide, 
and  the  slicer  is  plentifully  lubricated  with  the  oil  of  brick,  a 
thin  oil  that  is  used  on  account  of  its  limpidity,  and  not  being 
liable  to  become  thickened  by  exposure  to  the  atmosphere. 
Stones  of  small  or  moderate  size  -are  held  in  the  hand,  while  the 
arm  is  rested  upon  the  edge  of  the  bench  to  steady  it.  The 
stone  is  then  lightly  pressed  against  the  edge  of  the  slicer,  which 
is  driven  with  only  moderate  velocity,  or  the  friction  would  be 
liable  to  heat  the  stone,  and  cause  it  to  crack.  Care  should  be 
taken  in  the  commencement  of  the  cut  to  present  a  tolerably 
smooth  surface  to  the  slicer,  as  if  a  sharp  corner  were  first 
advanced,  it  would  be  liable  to  scrape  the  diamond  off  the  edge ; 
and  the  diamond  may  also  be  torn  off  the  edge  if  a  smooth  stone 
is  pressed  too  forcibly  against  the  slicer  with  the  view  of  expe- 
diting the  process.  During  the  slitting  the  slicer  should  be  kept 
plentifully  supplied  with  the  oil  of  brick,  and  the  stone  should 
be  held  steadily,  and  cautiously  managed  to  keep  the  cut  in  a 
straight  line,  as  from  the  concave  form  of  the  slicer  it  is  rather, 
liable  to  cut  upwards.  The  principal  attention  is  however 
required  at  the  first  commencement  of  the  cut,  and  if  this  be 
correctly  performed,  the  groove  will  serve  in  a  great  measure  as 
a  guide  for  the  completion  of  the  cut. 

When  the  stone  to  be  sliced  is  too  large  and  heavy  to  be  con- 
veniently held  in  the  hand,  it  is  mounted  on  the  crane,  as  shown 
in  fig.  1145.  The  crane  consists  of  an  upright  rod,  mounted 
between  centers,  just  in  front  of  the  perpendicular  bar  f>  and 
upon  this  rod  slides  vertically  a  horizontal  arm  j\  about  20  inches 
long,  provided  with  a  binding  screw,  by  which  it  may  be  fixed 
to  the  rod  at  any  height.  The  stone  to  be  sliced  is  fixed  to 
the  middle  of  the  arm  and  opposite  the  slicer,  by  means  of  a 
clamping  piece  and  two  binding  screws,  as  seen  in  the  figure,  and 


LAPIDARY  S    CRANE    FOB    SLICING    STONES. 


1312 


the  whole  is  drawn  forward  by  a  weight  £,  attached  to  a  line 
ling  from  the  extremity  of  the  horizontal  arm,  over  a  pulley 


fixed  to  the  end  of  the  bench.  The  stone  to  be  sliced  is  care- 
fully clamped,  so  that  the  line  of  the  intended  division  is  exactly 
horizontal,  and  the  precise  height  is  adjusted  by  sliding  the 
horizontal  arm  upon  the  vertical  rod,  until  the  line  of  division 
just  meets  the  edge  of  the  slicer.  The  weight  then  suffices  to 
keep  the  stone  continually  pressing  against  the  edge  of  the  slicer, 
and  the  operator  has  merely  to  keep  the  latter  in  motion,  and 
supply  the  oil. 

For  cutting  parallel  slices,  it  is  only  requisite  between  every 
cut,  to  shift  the  horizontal  arm  upwards  upon  the  vertical  rod. 
This  simple  contrivance  entirely  removes  all  difficulty  in  holding 
the  stone,  but  is  very  seldom  resorted  to  by  practical  lapidaries, 
except  for  large  stones.  A  modification  of  this  instrument  to 
adapt  it  to  the  use  of  amateurs  for  cutting  small  stones  will  be 
ereafter  adverted  to. 


To  remove  the  marks  made  by  the  slitting  mill,  the  flat  sur- 
of  the  stones  are  ground  upon  the  roughing  mill,  or  lead 
lap,  supplied  with  coarse  emery  and  water,  by  means  of  a  brush. 
If  the  stone  be  large  and  thick,  it  is  held  directly  in  the  fingers, 
but  more  generally  the  stones  are  too  thin  to  be  thus  held,  and 


1313  CEMENT    STICK CHARGING   THE    FLATTING    MILL. 


it  then  becomes  necessary  to  cement  them  to  a  wooden  stick  to 
serve  as  a  handle.  Large  thin  stones  would  also  be  liable  to  be 
broken  in  working  if  left  unsupported,  such  stones  are  therefore 
cemented  upon  a  handle  made  as  a  flat  disk  of  wood,  nearly  as 
large  in  diameter,  as  the  width  of  the  stone,  and  having  a  central 
stem  4  or  5  inches  long,  and  about  half  an  inch  diameter. 

The  cement  is  made  of  rosin,  tempered  with  bees-wax  and  a 
little  tallow,  and  hardened  with  red  ochre,  or  Spanish  brown 
and  whiting,  the  smaller  and  harder  the  stones,  the  harder  the 
cement  is  made  by  an  increased  quantity  of  the  powders.  For 
sapphires  and  other  hard  gems,  a  little  shell-lac  is  sometimes 
added  to  the  cement  to  increase  its  tenacity.  To  cement  the 
stone  upon  the  stick,  the  wooden  disk  is  first  warmed  over  a 
lamp,  or  candle,  the  cement  is  then  heated,  and  evenly  applied 
to  the  surface  and  edges  of  the  disk,  the  layer  of  cement  being 
made  sufficiently  thick  to  allow  of  the  stone  being  fairly  em- 
bedded, and  it  is  then  worked  with  the  fingers  nearly  to  the 
form  of  the  stone,  which  is  next  warmed  just  sufficiently  to 
cause  the  cement  to  adhere,  without  making  it  so  hot  as  to  be 
liable  to  burn  the  fingers ;  the  surface  of  the  cement  is  then 
melted  over  the  lamp,  and  the  warm  stone  is  immediately  pressed 
upon  it.  Care  should  be  taken  to  place  the  stone  quite  central 
with  the  stick,  which  should  also  be  exactly  at  right  angles  with 
the  flat  surface  of  the  stone.  The  cement  around  the  edges  of 
the  disk  is  then  worked  with  the  fingers  into  the  angle  around 
the  stone,  to  support  it  uniformly  near  the  edges. 

In  charging  the  lap  with  emery,  a  small  brush  dipped  in  water 
is  generally  applied  to  the  lap  to  moisten  it,  and  the  dry  emery 
is  then  sprinkled  over  its  surface,  and  rubbed  in  with  a  flat 
piece  of  emery  stone,  or  a  piece  of  sheet  iron ;  but  some  lapida- 
ries prefer  to  dip  the  moistened  brush  in  dry  emery,  and  then 
apply  it  to  the  lap.  In  whichsoever  way  the  emery  be  applied, 
it  is  desirable  that  as  much  emery  should  be  supplied  at  the 
commencement  of  the  roughing,  as  it  is  judged  will  suffice  for 
the  removal  of  the  marks  made  by  the  slicer,  and  should  more 
emery  be  required  as  the  work  progresses,  the  coarser  particles 
remaining  of  the  emery  first  supplied  are  partially  crushed, 
either  with  a  smooth  lump  of  emery  stone,  or  with  a  piece  of 
soft  sheet  Wn  about  1  inch  wide  and  8  inches  long,  and  the 
work  is  completed  with  a  finer  size  of  emery,  so  as  gradually  to 


ROUGHING    AND    SMOOTHING    FLAT    SURFACES.  1314j 

reduce  the  coarseness  of  the  grinding  powder  as  the  flat  surface 
is  approached. 

As  mentioned  at  page  1034,  under  the  head  ALABASTER, 
Article  3,  many  lapidaries  employ  the  same  lead  mill,  both  for 
roughing  and  smoothing  the  surface  of  the  stones  ;  some  lapida- 
ries however  employ  two  benches  for  these  purposes,  so  tbat  the 
work  may  be  taken  from  the  roughing  mill  to  the  smoothing 
mill,  without  the  loss  of  time  incurred  in  crushing  the  coarser 
emery  quite  fine,  but  when  one  bench  only  is  used  for  the 
roughing  and  smoothing,  the  same  lap  is  made  to  serve  both  pur- 
poses. For  large  stones,  the  roughing  is  generally  commenced 
with  grinding  emery,  and  finished  with  flour  emery ;  but  for  small 
stones,  superfine  grinding  emery  is  sufficiently  coarse  for  the 
commencement,  and  fine  flour  emery  is  used  for  the  smoothing. 

In  applying  the  stone  to  the  mill,  it  is  placed  flat  on  the 
surface,  and  firmly  pressed  with  the  ends  of  the  fingers  and 
thumb  applied  on  the  back  of  the  wooden  disk,  the  upright 
stem  passing  between  the  fore  and  middle  fingers.  If  the  stone 
be  large,  it  may,  with  advantage,  at  the  commencement,  be 
rubbed  upon  the  flat  face  of  the  revolving  mill  with  small  cir- 
cular strokes,  and  at  the  same  time  the  stone  may  be  slowly 
twisted  round  with  the  fingers,  in  order  to  expose  it  equally  to 
the  action  of  the  mill.  If  the  stone  be  small  it  must  be  held 
quite  steady  throughout  the  process,  but  in  order  to  wear  the 
lap  uniformly,  the  stone  is  placed  in  a  different  position  every 
time  that  it  is  rested  on  the  mill. 

The  velocity  of  the  mill  employed  in  grinding  should  be  only 
moderate,  so  as  just  to  avoid  throwing  off  much  of  the  grinding 
powder  with  the  centrifugal  force ;  the  progress  of  the  work 
may  be  expedited  by  using  a  higher  velocity,  but  the  emery  and 
water  are  then  thrown  off  so  abundantly  as  to  be  very  objection- 
able, and  the  condition  of  the  work  can  be  less  delicately  felt. 
The  stone  should  also  be  pressed  upon  the  mill  with  only  mode- 
rate force,  as  great  pressure  is  liable  to  cause  the  stone  to  push 
away  the  loose  particles  of  grinding  powder,  and  also  to  wear 
the  mill  irregularly,  whereas  moderate  pressure  allows  the  loose 
particles  of  emery  to  roll  over  between  the  mill  and  stone,  and 
the  work  then  progresses  more  rapidly,  and  the  mill  is  less 
injured. 

The  stone  having  been  made  as  smooth  as  practicable  with 

VOL.  III.  U 


1315  CUTTING    THE    EDGES    OF    STONES    TO    DEFINE    FORMS. 


the  emery,  the  polishing  is  proceeded  with  in  the  same  manner, 
upon  a  mill  of  appropriate  material,  generally  pewter,  hacked, 
or  jarred,  as  explained  under  the  head  CARNELIAN,  page  1044, 
and  supplied  with  rottenstone  and  water.  This  completes  the 
one  side  of  the  stone,  and  it  is  then  detached  by  heat  from  the 
cement  stick ;  and  the  same  routine  is  followed  with  the  second 
side. 

If  the  stone  is  required  to  be  wrought  to  a  definite  shape,  as 
for  example  an  oval,  the  edge  is  ground  to  the  oval  form  before 
the  sides  are  flattened.  For  this  purpose  a  corresponding  oval 
is  cut  out  of  card  to  the  exact  dimensions,  and  laid  upon  the 
stone ;  the  oval  is  then  marked  with  ink  upon  the  stone,  which  is 
brought  very  nearly  to  the  shape  by  means  of  nippers,  or  flat 
pliers  of  soft  iron,  like  those  employed  for  rounding  disks  of 
glass  preparatory  to  grinding  them  into  lenses,  see  page  1265 ; 
the  nippers  are  firmly  compressed  upon  the  stone,  and  then 
twisted  sideways  to  break  off  small  particles.  The  hardest 
stones,  such  as  sapphires,  will  yield  to  the  action  of  the  nippers, 
although  they  are  scarcely  ever  used  with  valuable  gems ;  but  if 
the  stones  are  smooth  and  rounded  like  the  natural  surface  of  a 
pebble,  the  nippers  will  slide  off,  and  therefore  such  stones  are 
first  slightly  roughened  to  give  a  hold  to  the  nippers. 

The  stone  having  been  nipped  of  the  required  shape,  and 
nearly  to  the  size,  it  is  cemented  upon  a  stick,  the  edge  being 
left  exposed,  and  this  is  then  ground  square  by  holding  the  stick 
horizontally,  and  continually  twisting  it  round  between  the 
fingers  to  avoid  grinding  flat  places ;  when  the  stone  has  been 
thus  figured  to  the  required  shape,  the  flat  face  is  ground  and 
polished. 

If  the  stone  is  required  to  have  a  bevelled  edge,  or  chamfer 
around  the  face,  the  stone  is  first  nipped  to  the  form,  then  fixed 
on  the  cement  stick,  with  the  side  outwards  that  is  to  form 
the  back  of  the  stone ;  the  edge  is  ground  square  and  the  back 
flattened  and  polished  if  necessary.  The  stone  is  then  re- 
cemented  upon  the  stick  with  the  face  side  outwards  ;  the  face  is 
flattened,  and  the  bevelled  edge  is  then  ground  by  holding  the 
stick  at  an  angle,  and  continually  twisting  the  stone  round  to 
grind  the  chamfer  uniformly.  The  thickness  of  the  narrow 
square  edge  left  on  the  stone,  serves  as  a  sufficient  guide  for 
practised  lapidaries  to  ensure  the  uniformity  of  the  bevel,  but 


CUTTING   ROUNDED    SURFACES    ON    STONES.  1316 

the  amateur  will  probably  find  it  desirable  to  mark  a  line  on  the 
edge,  and  also  the  face  of  the  stone,  to  show  how  far  the  chamfer 
should  extend. 

If  the  stone  is  to  have  a  rounded  edge,  it  is  first  prepared 
with  a  bevelled  edge  exactly  as  above,  and  the  angle  is  removed 
by  a  rocking  motion  of  the  stone  upon  the  flat  mill.  For  this 
purpose  the  stick  is  held  underhand,  being  grasped  between  the 
fingers  as  near  to  the  bottom  as  admissible,  and  the  stick  is 
continually  traversed  from  nearly  the  perpendicular  position  to 
the  angle,  at  which  the  chamfer  was  ground.  The  wrist  or 
elbow  being  the  center  of  motion  according  to  the  curvature 
required,  and  at  the  same  time  the  stick  is  twisted  round  in  the 
fingers,  in  order  to  round  the  edge  uniformly. 

If  the  stone  is  to  be  considerably  rounded  over  the  entire  face, 
the  preparatory  step  of  grinding  the  face  flat  may  be  omitted,  as 
the  stone  will  be  left  sufficiently  level  by  the  slicer,  and  the  prin- 
cipal bulk  of  the  material  is  removed  by  the  chamfer,  which 
serves  as  the  basis  or  guide  for  keeping  the  rounding  uniform, 
assisted  during  the  principal  portion  of  the  work  by  the  central 
part  of  the  stone,  not  reached  by  the  rounding  until  near  the 
conclusion  of  the  rough  grinding. 

If  the  stone  to  be  rounded  on  the  face  be  circular,  it  is  rolled 
upon  the  flat  mill  with  circular  strokes;  between  every  few 
strokes  it  is  shifted  to  another  part  of  the  mill,  and  the  stick  is 
continually  twisted  round  in  the  fingers.  If  the  stone  be  of  a 
short  elliptical  shape,  it  is  treated  in  the  same  manner,  except 
that  it  is  traversed  in  an  elliptical  path.  In  the  case  of  very 
long  ellipses,  the  two  sides  of  the  ellipsis  are  first  ground  sepa- 
rately with  a  rocking  motion,  and  the  stick  is  slightly  twisted  in 
the  fingers  between  every  few  strokes.  The  ends  of  the  ellipsis 
are  rounded  in  the  same  manner,  and,  lastly,  it  is  smoothed  with 
long,  semi- elliptical  strokes.  The  principal  guide  for  the  degree 
of  rolling  is  obtained  from  an  inspection  of  the  progress,  but  the 
sense  of  feeling  is  also  greatly  trusted  to  by  working  lapidaries. 
Stones  that  are  flat  on  the  back,  and  much  rounded  on  the 
front,  are  called  tallow  tops,  from  their  resemblance  to  a  drop 
of  tallow. 

Stones  that  are  rounded  to  a  cylindrical  or  conical  form,  such 
as  a  drop  for  an  earring,  are  cemented  sideways  upon  a  stick, 
and  the  one-half  ground  to  the  semi-circular  section ;  they  are 

u2 


1317  CUTTING    ROUNDED    SURFACES    ON    STONES. 

then  detached  from  the  stick,  and  cemented  with  the  other  side 
outwards,  and  this  is  similarly  wrought.  Of  course,  some  care 
is  required  to  grind  the  two  semi-circular  sections  exactly  oppo- 
site to  each  other ;  and  when  this  has  been  done  as  nearly  as 
possible,  the  stone  is  successively  cemented  in  two  other 
positions  at  right  angles  to  the  first  two,  in  order  to  expose  the 
junctures  of  the  two  curved  surfaces  first  produced,  and  which 
are  then  corrected. 

Stones  that  are  to  be  ground  into  spheres,  for  beads  or  the 
heads  of  pins,  are,  in  like  manner,  required  to  be  cemented  in 
at  least  four  positions  before  they  can  be  brought  sufficiently 
near  to  the  required  form.  The  method  of  grinding  spheres 
perfectly  true  has  been  already  explained  in  sect.  iv.  of  the 
foregoing  chapter ;  but,  of  course,  this  amount  of  accuracy  is 
not  required  for  lapidary  purposes,  as,  generally,  the  form  is 
only  required  to  be  sufficiently  correct  to  satisfy  the  eye.  With 
the  view  of  expediting  the  process  of  grinding  stones  that  are 
much  rounded,  and  also  to  preserve  the  lap  used  for  flat  surfaces, 
one  lap  is  generally  set  aside,  to  be  used  only  for  rounded  works, 
and,  from  constant  use,  the  side  of  this  lap  becomes  worn  into 
numerous  hollows,  of  different  sizes,  some  of  which  are  generally 
found  to  nearly  fit  the  curve  of  the  stone  being  ground.  This 
materially  lessens  the  difficulty  of  producing  spherical  surfaces, 
and  the  edge  of  the  same  lap  is,  in  general,  rounded  off,  to  serve 
for  concave  works. 

In  grinding  a  pebble  to  the  shape  of  a  heart  with  rounded 
sides,  the  pebble,  if  much  thicker  than  the  intended  heart,  is 
first  cut  to  the  suitable  thickness  with  the  slicer ;  it  is  then 
marked  from  a  card  pattern,  and  nipped  nearly  to  the  form  and 
size.  The  edges  are  then  squared,  the  square  angle  of  the  lap 
being  employed  for  making  the  indentation  at  the  top  of  the 
heart.  So  far,  the  stone  is  generally  held  in  the  fingers ;  and 
when  the  outline  has  been  thus  produced,  the  stone  is  cemented 
on  a  stick,  the  edges  are  chamfered  all  round,  and  the  stone  is 
rough-ground  to  the  rounded  form,  smoothed,  and  polished  ;  the 
second  side  is  then  treated  in  the  same  manner. 

Small  stones  cut  in  the  form  of  a  shield,  as  for  a  signet  ring, 
are,  in  the  same  manner,  first  wrought  to  the  outline  of  the 
shield  while  held  in  the  fingers,  although  these  stones  are  often 
not  more  than  one  quarter  of  an  inch  in  height.  In  holding  such 


CUTTING    HOLLOWS    AND   MOULDINGS    ON    STONES.  1318 

small  stones,  some  care  is,  of  course,  required  to  avoid  bringing 
the  fingers  in  contact  with  the  lap,  which  would  be  likely  to 
grind  through  the  skin  even  before  the  operator  was  fairly  aware 
that  they  touched  the  lap,  the  grinding  action  being  almost 
insensible  until  the  outer  coat  of  the  skin  is  worn  through. 

Stones  that  are  semi-transparent,  such  as  garnets,  are  fre- 
quently left  round  on  the  face,  or  cut  en  cabochon;  but  such 
stones,  if  left  of  the  full  thickness,  would  be  too  opake  to  display 
much  brilliancy  ;  and,  therefore,  with  the  view  of  increasing  the 
transparency,  garnets  cut  en  cabochon,  and  called  carbuncles,  are 
generally  hollowed  on  the  under  side,  to  make  them  thinner. 
The  hollow  on  the  under  side  is  ground  upon  small  spherical 
grinders  of  lead,  called  balls,  made  of  various  thicknesses  and 
diameters,  but  mostly  about  the  size  of  bullets.  The  balls  are 
mounted  upon  a  small  conical  spindle,  that  is  fitted  to  the  ordi- 
nary lapidary's  bench ;  the  hole  through  the  balls  is  also  made 
slightly  conical,  so  that  they  may  be  retained  upon  the  spindle 
by  the  plain  fitting,  and  allow  of  being  readily  detached  for  the 
substitution  of  other  balls  of  different  sizes.  Similar  balls,  made 
of  pewter,  are  employed  for  polishing ;  and  it  is,  of  course, 
necessary  that  the  grinding  and  polishing  balls  should  be,  as 
nearly  as  possible,  of  the  same  size. 

For  cutting  small  mouldings,  or  hollows,  in  the  edges  or  sides 
of  stones,  the  lapidary  employs  little  lead  mills,  not  exceeding 
about  three  inches  diameter ;  they  are  generally  held  by  a 
plain  fitting,  upon  the  same  spindle  that  carries  the  ordinary 
mills,  and  which  is  made  somewhat  conical  for  the  purpose.  The 
edges  of  these  mills  are  principally  used,  and  they  are  made  of 
various  shapes  and  thicknesses,  but  mostly  with  rounded  or 
angular  edges,  in  order  to  penetrate  the  cavities  of  hollow 
mouldings,  and  the  rounded  parts  are  chiefly  produced  by  rolling 
the  work  over  the  edges.  The  small  diameter  of  these  mills 
allows  of  delicate  works  being  better  seen,  and,  from  the  velocity 
being  less  at  the  edge  of  the  mill,  the  position  and  progress  of 
the  work  is  also  more  readily  appreciated  by  the  sense  of  feeling. 

In  cutting  a  seal-handle,  with  an  octagonal  section,  and  a 
rounded  top,  such  as  fig.  1146,  the  stone  is  first  sliced  into  the 
pyramidal  form  indicated  by  the  dotted  lines ;  the  sides  are  then 
flattened  and  the  angles  removed  upon  the  ordinary  roughing 
mill,  to  bring  the  stone  to  the  octagonal  section,  and  the  top  is 


1319 


CUTTING    SEAL   HANDLES. 


rounded.     The  indentations  at  a  a  are  then  cut  upon  the  angle 
of  a  mill  having  a  square  edge.      The  curved  portion  at  b  is 
FIGS.  1146.  1147. 


cut  upon  a  mill  with  a  slightly  rounded  edge,  which  also  serves 
for  removing  the  principal  portion  of  the  material  from  the 
large  hollows  iit  c ;  and  these  are  afterwards  corrected  either 
by  applying  the  stone  transversely  upon  a  lap  with  a  rounded 
edge,  turned  to  the  required  curvature,  or  by  applying  the  stone 
longitudinally  upon  a  square-edged  mill,  of  about  two  inches 
diameter,  the  curvature  of  which  would  correspond  with  the 
hollows  in  the  figure.  The  small  flutes  in  the  rounded  top  are 
cut  with  a  mill  of  small  diameter,  having  a  narrow  rounded  edge. 
In  cutting  the  handle,  figs.  1148  and  1149,  the  stone  is  roughed 
out  to  the  general  contour  upon  mills  with  rounded  edges  of  appro- 
priate thicknesses.  The  stone  is  first  wrought  of  an  elliptical 
section  throughout,  by  continually  twisting  it  round  in  the  fingers. 
The  two  longest  sides  are  then  flattened  by  holding  the  stone 
firmly  in  the  fingers,  and  traversing  it  backwards  and  forwards 
a  small  distance  upon  the  edge  of  the  mill ;  the  four  angles  are 
removed  in  the  same  manner,  and  the  two  narrow  ends  of  the 
irregular  octagon  are  formed  by  portions  of  the  original  ellipsis, 
the  curvature  being  scarcely  perceptible  in  the  lower  part  of  the 
handle.  The  two  large  flutes,  a,  are  cut  by  traversing  the  stone 
over  a  mill  of  about  two  inches  diameter,  with  a  rounded  edge  ; 
and  the  four  small  flutes  are  cut  upon  a  similar  mill,  of  smaller 
diameter. 


DRILLING    SMALL    AND    LARGE    HOLES    IN    STONES.  1320 

In  all  these  cases,  no  guide  whatever  is  employed  for  pro- 
ducing the  form,  the  perfection  of  which  depends  entirely  upon 
the  figure  of  the  edge  of  the  mill,  and  the  dexterity  of  the 
workman.  Sharp  internal  angles  are  not  often  attempted,  as  it 
is  difficult  to  maintain  the  sharp  angle  of  the  grinder. 

The  minute  cutting  on  the  surfaces  of  small  works,  such  as 
coral  drops  for  ear-rings,  and  similar  objects,  is  performed  by 
another  class  of  artizans,  who  mount  small  angular,  flat,  or 
rounded  grinders,  upon  horizontal  spindles  in  the  ordinary  lathe, 
and  apply  the  work  beneath  the  grinders,  in  much  the  same 
manner  as  the  glass-cutters ;  indeed,  the  coral  cutting  may  be 
considered  to  form  a  link  between  glass- cutting,  and  seal  engrav- 
ing, described  respectively  in  sect,  v.,  chap,  xxxiii.,  and  sect,  iii., 
chap.  xxxv. 

For  perforating  very  small  holes  through  beads  and  similar 
objects,  the  lapidary  employs  as  a  drill  a  small  steel  or  iron  wire, 
such  as  fig.  67}  page  178,  Vol.  I.  The  wire  is  mounted  in  a 
chuck,  to  revolve  horizontally  upon  an  ordinary  lathe  mandrel, 
and  is  charged  with  diamond  powder  in  the  same  manner  as  the 
sheer.  For  holes  more  than  about  the  twentieth  of  an  inch 
diameter,  tubular  drills  are  used,  such  as  fig.  71,  made  of  thin 
sheet  iron,  bent  around  a  small  central  wire.  These  drills  remove 
a  small  solid  core,  which  breaks  when  the  tube  has  penetrated 
some  little  distance,  and  the  core  is  pushed  out  of  the  tube  by 
passing  a  fine  needle  through  a  hole  in  the  side. 

Larger  tubes  are  employed  in  the  same  manner  for  cutting 
out  the  circular  holes  sometimes  made  in  large  brooches  for  the 
insertion  of  another  stone,  or  a  locket.  If  the  hole  is  required 
to  be  oval,  two  circular  holes  of  suitable  size  are  made  to  consti- 
tute the  two  ends  of  the  oval,  and  the  little  angular  pieces  left 
between  the  two  circles  are  removed  with  a  small  conical  grinder. 
Small  tubes  are  soldered  upon  the  metal  wires,  but  those  exceed- 
ing about  half  an  inch  in  diameter  are,  by  the  lapidary,  generally 
attached  by  cement  to  a  wooden  chuck.  These  annular  drills 
are  sometimes  made  as  large  as  from  one  to  two  inches  diameter, 
and  thus  the  lapidary's  tubular  drills  are  carried  up  to  the  size 
of  the  smallest  circular  cutters  or  grinders  used  for  similar  pur- 
poses in  marble,  as  alluded  to  in  page  1208  of  the  present 
volume. 


1321  CUTTING    FACETS. 


SECTION    II. CUTTING    FACETS. 

THE  surfaces  of  gems,  pastes,  and  most  other  substances 
worked  by  the  lapidary,  are,  as  is  well  known,  cut  into  facets  to 
improve  their  brilliancy,  by  multiplying  the  number  of  reflecting 
surfaces,  in  order  that  the  play  of  light  may  be  proportionally 
increased.  Facets  are  principally  cut  upon  transparent  and 
semi-transparent  stones,  but  sometimes  also  upon  opake  stones, 
such  as  carnelian  ;  and  speaking  generally,  it  may  be  said  that 
the  greater  the  natural  brilliancy  of  the  stone,  the  fewer  facets 
are  necessary  to  produce  the  required  play  of  light ;  and  with 
valuable  gems  it  is  always  desirable  to  produce  the  brilliancy 
with  as  few  facets  as  possible,  in  order  to  avoid  confusion  in  the 
rays  of  light. 

Opake  stones  are  cut  on  the  face  only,  and  the  stone  is  in 
general  thin,  and  flat  on  the  back  ;  but  transparent  stones  are,  if 
possible,  left  thick,  and  so  cut  as  to  make  the  back,  or  lower 
part  of  the  stone  that  is  enclosed  in  the  setting,  of  about  double 
the  thickness  of  the  front  or  face  that  is  exposed.  The  back  of 
the  stone  is  cut  into  facets  or  squares  that  exactly  correspond 
in  plan  with  the  position  of  the  principal  facets  on  the  front  of 
the  stone ;  and  the  angles  which  the  squares  at  the  back  make 
with  the  axis  of  the  stone,  are  required  to  be  such,  that  all  the 
light  reflected  from  their  surfaces,  may  fall  within  the  central 
flat  surface  on  the  front  of  the  stone,  called  the  table. 

The  facets  are  arranged  upon  the  stones  in  a  great  variety  of 
methods,  but  they  may  nearly  all  be  considered  as  modifications 
of  three  principal  varieties,  namely,  the  trap  cut,  the  brilliant  cut, 
and  the  rose  cut,  one  of  the  two  latter  forms  being  always 
employed  for  diamonds. 

The  trap  cut,  or  trapping,  as  it  is  called  by  lapidaries,  consists 
of  parallel  planes  nearly  rectangular,  arranged  round  the  contour 
of  the  stone,  as  shown  in  figs.  1151  to  1156.  This  cut  is  always 
used  for  emeralds,  and  sometimes  also  for  the  fronts  of  other 
gems,  but  it  is  principally  employed  for  the  backs  of  stones,  the 
fronts  of  which  are  cut  in  one  of  the  modifications  of  the  brilliant 
cut. 

The  brilliant  cut  consists  of  lozenge-shaped  facets  alternated 
with  triangles,  as  shown  in  figs.  1 1 57  to  1167,  and  is  used  for  the 
fronts  of  most  transparent  stones  that  are  sufficiently  thick  to 


; 


DIFFERENT    FORMS    OF    FACETTING.  1322 

allow  of  being  cut  into  facets  on  both  the  front  and  back.  The 
different  modifications  of  this  form  of  facetting,  are  known  as 
the  half  brilliant,  or  single  cut ;  the  full  brilliant ;  the  split  bril- 
liant, or  trap  brilliant ;  and  the  double  brilliant,  or  Lisbon  cut ; 
according  to  the  arrangement  of  the  principal  facets. 

The  rose  cut  consists  of  triangular  facets  arranged  upon  and 
around  a  central  hexagon,  as  in  figs.  1169  to  1173.  This  cut  is 
employed  upon  such  stones  as  are  thin,  and  large  on  the  surface, 
or,  as  it  is  called,  much  spread,  as  the  rose  cut  is  applied  only  on 
the  front  of  the  stone,  and  the  back  is  left  flat.  The  rose  cut  is 
considered  to  give  the  greatest  lustre  that  can  be  obtained  from 
cutting  the  front  only,  as  the  surface  is  entirely  covered  with 
facets,  and  on  this  account  the  rose  cut  is  sometimes  applied  to 
opake  stones,  but  its  principal  application  is  to  the  diamond,  or 
to  other  colourless  gems  employed  as  fictitious  diamonds,  such  as 
the  jargoon. 

In  all  cases  of  cutting  valuable  gems,  the  principal  object  of 
the  lapidary  is  to  fashion  the  stone  so  as  to  produce  as  much 
display  as  can  be  attained  without  materially  reducing  the  size 
of  the  gem,  and  this  circumstance  in  great  measure  determines 
the  manner  in  which  it  is  cut.  This  is  especially  the  case  with 
the  diamond,  which  is  always  found  in  the  form  of  an  octahedron, 
more  or  less  perfect  in  form  ;  and  unless  the  diamond  has  defects, 
it  is  always  cut  as  a  brilliant,  with  an  octagonal  base,  that  being 
the  largest  regular  figure  that  can  be  inscribed  within  the 
octahedron. 

Diamonds  that  have  defects  are  split  by  cleavage,  and  the 
pieces  are  cut  into  rose  diamonds,  and  which  form  is  also  adopted 
for  those  whole  diamonds  that  are  too  thin  to  be  cut  into  bril- 
liants. Other  valuable  gems  are  in  like  manner  cut  into  the 
largest  regular  forms  they  will  respectively  produce. 

With  less  valuable  stones  and  pastes,  the  reduction  of  the 
aterial  is  of  less  importance,  and  the  form  of  cutting  is  rather 
matter  of  choice  than  otherwise  ;  but  in  order  that  they  may 
lie  more  nearly  resemble  valuable  gems,  they  are  usually  cut 
into  corresponding  forms ;  this  is  especially  the  case  with  pastes, 
which  are  cut  on  the  front  in  exactly  the  same  manner  as  the 
gems  they  are  intended  to  represent,  and  the  cutting  at  the  back 
is  only  modified,  so  as  to  cause  the  play  of  light  to  assimilate  to 
that  of  the  gems  themselves. 


1323  PREPARATION    OF    STONES    FOR   RECEIVING    FACETS. 


In  all  cases  of  cutting  gems  or  pastes  into  facets,  the  general 
contour  of  the  stone  is  first  produced  by  roughly  grinding  it  into 
form,  much  the  same  as  for  a  rounded  stone.  Generally  the 
first  step  is  to  grind  a  flat  face  upon  the  stone,  in  order  to  judge 
of  its  quality,  and  ascertain  whether  it  contains  any  imperfec- 
tions, and,  if  so,  the  cutting  is  modified  accordingly.  If  the 
stone  proves  to  be  tolerably  perfect,  and  it  is  to  be  cut  into  facets 
upon  both  the  front  and  back,  the  flat  surface  first  cut  is  made  to 
constitute  the  table  of  the  stone,  and  the  edges  are  corrected  to 
bring  it  to  a  regular  figure,  generally  a  circle  or  ellipsis,  but 
sometimes  a  square,  or  rectangle,  with  the  corners  rounded  off, 
according  to  the  shape  that  can  be  produced  with  the  least  waste 
of  material.  The  edge  thus  ground  forms  the  girdle,  or  extreme 
margin  of  the  stone  by  which  it  is  retained  in  the  setting.  The 
part  between  the  girdle  and  table,  called  the  top  of  the  stone,  is 
then  rounded  or  bevelled  off  to  about  the  extent  that  the  facets 
are  desired  to  extend.  The  back  of  the  stone  is  afterwards 
rounded  in  the  same  manner  to  the  general  shape,  leaving  a 
small  central  plane  called  the  cullet,  or  cullasse. 

If  the  stone  is  to  be  cut  into  facets  on  the  front  only,  the  flat 
face  first  cut  is  mostly  made  to  constitute  the  back  of  the  stone, 
the  edges  are  corrected  for  the  girdle,  and  the  front  is  prepared 
by  cutting,  first,  a  flat  face  for  the  table,  and  afterwards  rounding 
or  bevelling  the  top.  So  far  the  stones  are  prepared  in  the  same 
manner  to  the  general  shape,  whatsoever  form  of  facetting  is  to 
be  adopted. 

The  square  cut,  or  trap  cut,  is  the  most  simple  form  of  cutting 
facets,  and  also  serves  as  the  foundation  of  the  facets  of  the  bril- 
liant cut.  The  method  of  producing  the  trap  cut  will  be  there- 
fore first  described,  and  this  will  be  followed  by  some  observations 
on  the  brilliant  cut.  In  order  to  avoid  confusion,  it  will  be  more 
convenient  to  limit  the  majority  of  the  examples  to  elliptical 
stones  cut  with  eight  principal  planes  or  facets,  one  on  each  of 
the  sides  of  an  irregular  octagon.  Stones  are  frequently  cut  with 
as  many  as  twelve  or  fourteen  sides,  but  the  general  method  is 
exactly  the  same,  whatever  may  be  the  number  of  sides. 

Fig.  1151  represents  in  plan,  and  fig.  1152  in  side  elevation, 
stone  cut  on  the  face  only  with  a  single  row  or  height  of  eig 
planes  or  squares  connecting  the  central  table  with  the  girdl 
In  cutting  this  form,  the  stone  is  cemented  upon  a  stick  with 


TRAP    OR    SQUARE    CUT. 


1324 


side  to  constitute  the  back  outwards ;  this  is  then  ground  flat, 
the  edge  cut  into  shape  for  the  girdle,  and  the  back  polished ; 
the  stone  is  then  re-cemented  upon  the  stick  with  the  front  out- 
wards. The  stick  should  be  a  little  smaller  in  diameter  at  the 
end  than  the  size  of  the  stone,  which  requires  to  be  placed  exactly 
central  on  the  stick,  and  with  the  flattened  back  as  nearly  as  pos- 
sible at  right  angles  to  the  axis  of  the  stick,  in  order  that  the 
table  may  be  cut  parallel  with  the  back,  and  also  that  the  squares 
on  the  top  may  be  all  cut  at  the  same  angle. 

The  cutting  on  the  front  of  the  stone  is  commenced  by  grinding 
the  flat  table ;  a  uniform  bevel  is  then  cut  around  the  top.  The 
bevel  is  made  of  about  the  width  of  the  desired  squares,  and  is 
called  a  water  lasil,  from  its  running  uninterruptedly  around  the 
stone.  So  far  the  process  is  exactly  the  same  as  for  cutting  an 
elliptical  stone  with  a  bevelled  edge. 

The  eight  squares,  or  facets,  are  then  cut  upon  the  bevelled 
edge.  For  this  purpose  the  stone  is  applied  to  the  mill  as  shown 
in  fig.  1150,  the  gim  peg,  #,  being  adjusted  for  position,  until  upon 
trial  it  is  found  that,  on  placing  the  stone  fairly  upon  the  lap 


FIG.  1150. 


1325 


TRAP    OR    SQUARE    CUT. 


or  mill,  and  inserting  the  upper  end  of  the  stick  in  one  of  the 
notches  in  the  wooden  socket,  the  stick  is  inclined  at  the  same 
angle  as  that  at  which  the  water  basil  was  ground.  The  gim  peg 
is  then  fixed  by  the  wing  nut  beneath  the  bench,  and  the  wooden 
socket  secured  by  the  wedge ;  the  mill  is  then  put  in  revolution, 
and  the  stone  is  applied,  first  to  cut  the  two  facets  on  the  longest 
sides  opposite  to  each  other,  and  then  those  at  the  two  ends  are 
cut  as  nearly  square  as  practicable,  under  the  guidance  of  the  eye 
alone ;  lastly,  the  four  squares  at  the  corners  are  cut  to  bring  the 
stone  to  the  octagonal  form. 

The  four  planes  first  cut  at  right  angles  serve  as  the  basis  of 
the  figure,  and  some  care  and  practice  are  required  to  place  them 
exactly  square,  but  the  process  is  less  difficult  than  might  be 
FIGS.  1151.  1153. 


1152. 


1154. 


\      \ 


anticipated,  as  in  cutting  the  first  pair  of  opposite  planes,  it 
may  be  readily  perceived  whether  or  not  they  are  parallel,  and 
should  they  not  be  correctly  placed  at  the  first  attempt,  the 
stick  is  slightly  twisted  in  the  hand  for  changing  the  position 
of  the  squares.  But  little  pressure  is  exerted  upon  the  stone, 
with  the  fingers  applied  above  the  stick  and  as  near  to  the  stone 
as  convenient.  The  square  position  of  the  pair  of  planes  at  the 
two  ends,  may  in  like  manner  be  estimated  very  nearly  by  a  prac- 
tised eye,  and  these  foundation  squares  having  been  correctly 
placed,  the  position  of  the  four  squares  at  the  corners  is  tolerably 
easy  of  attainment,  and  these  squares  are  gradually  enlarged 
until  the  desired  figure  is  produced.  In  elliptical  stones  the 
corner  squares  are  mostly  smaller  than  the  others,  in  order  to 
avoid  the  reduction  of  the  material.  In  cutting  a  stone  with 


TRAP    OR    SQUARE    CUT. 


1326 


twelve  squares  on  the  same  height,  the  four  squares  at  right 
angles  are  first  cut  in  the  same  manner,  and  the  figure  is  com- 
pleted by  cutting  two  facets  at  each  of  the  four  angles,  instead  of 
one  only  as  for  the  octagon.  Stones  with  ten  or  fourteen  facets 
on  the  one  row  are  rather  more  difficult  to  cut  by  hand,  as  only 
the  two  opposite  facets  in  the  middle  can  be  derived  from  the 
square  figure. 

Figs.  1158  and  1154  represent  a  thicker  stone  trapped  in  two 
eights,  or  cut  with  two  rows  of  square  facets,  one  above  the 
other,  and  placed  at  different  angles  with  the  table  of  the  stone. 
The  row  of  squares  adjoining  the  girdle  is  always  left  somewhat 
wider  than  that  adjoining  the  table,  partly  with  the  view  of 
compensating  for  the  narrow  portion  enclosed  in  the  setting* 

The  stone  is  prepared  in  exactly  the  same  manner  as  for  a 
single  height  of  trapping,  except  that  two  water  basils  of  the 
desired  widths  of  the  squares,  are  cut  upon  the  top  of  the  stone. 
The  row  of  squares  near  the  girdle  is  first  cut,  the  cement  stick 
being  inserted  in  the  same  hole  in  the  gim  peg  for  cutting  every 
square  in  the  same  row.  The  row  of  squares  adjoining  the  table 
is  then  cut  in  the  same  manner,  except  that  the  stick  is  inserted 
in  a  higher  hole  in  the  gim  peg,  in  order  to  place  the  squares  at 
a  greater  angle ;  and  some  care  is  required  to  cut  the  upper  row 
exactly  opposite  the  lower. 

As  previously  mentioned,  transparent  stones,  that  are  of  suffi- 
cient thickness,  are  generally  cut  both  on  the  front  and  back.  In 
this  case  about  one-third  of  the  entire  thickness  is  given  to  the 
front,  and  about  two-thirds  to  the  back,  as  shown  in  figs.  1155 
and  1156,  which  represent  the  side  elevation  and  back  plan  of  a 


FIGS.  1155. 


1156. 


stone  trapped  in  two  heights  or  rows  of  squares  on  the  front, 
like  fig.  1154,  and  three  heights  at  the  back,  a  style  of  cutting 


1327  TRAP    OR    SQUARE    CUT. 

frequently  adopted  for  small  emeralds  and  other  stones.  Those 
of  medium  size  have  generally  four  heights  on  the  back,  and  very 
large  emeralds  sometimes  have  three  heights  of  trapping  on  the 
face,  and  from  five  to  eight  heights  on  the  back;  but  with  eme- 
ralds the  trap  cut  is  not  often  carried  to  the  latter  degree  of 
elaboration,  unless  it  be  done  with  the  view  of  keeping  the  gem 
as  heavy  as  possible,  as  the  greater  the  number  of  heights  in  the 
trapping,  the  more  roundness  can  be  given  to  the  general  contour 
of  the  back,  and  consequently  greater  weight  to  the  stone ;  but 
if  the  convexity  be  too  great,  it  detracts  from  the  lustre  of  the 
gem. 

In  cutting  a  stone  to  the  form  of  fig.  1155,  it  is  cemented  on  a 
stick,  the  flat  surface  of  the  table  is  first  cut,  and  the  edge  is 
brought  to  the  desired  shape  of  the  girdle.  Two  water  basils  are 
then  cut  around  the  top,  in  the  same  manner  as  for  fig.  1154,  but 
the  facets  on  the  front  are  not  cut  until  the  back  has  been  com- 
pleted ;  for  this  purpose  the  stone  is  re-cemented  upon  the  stick, 
and  the  back  is  rounded  to  the  general  form  ;  a  single  water  basil 
is  then  cut  around  the  girdle,  to  determine  the  height  of  the  first 
row  of  squares,  and  these  squares  are  next  cut,  with  the  aid  of 
the  gim  peg ;  the  second  row  of  squares  are  then  cut  in  like 
manner,  but  without  the  preparatory  step  of  cutting  the  water 
basil,  as  the  first  row  of  squares  serves  as  a  sufficient  guide  for 
keeping  the  squares  in  the  second  row  uniform ;  the  third  row  of 
squares  is  cut  in  the  same  manner,  the  cement  stick  being  shifted 
to  a  higher  notch  in  the  gim  peg  between  every  row  ;  and,  lastly, 
the  stick  is  held  vertical  to  cut  the  culasse. 

The  squares  are  then  polished  in  the  same  order,  the  gim  peg 
being  carefully  adjusted  for  height  between  every  row,  in  order 
that  the  stick  may  be  inclined  at  exactly  the  same  angle  as  that 
employed  for  cutting  the  squares.  As  mentioned  in  the  cata- 
logue, a  pewter  mill  supplied  with  rottenstone  and  water  is  em- 
ployed for  polishing  stones  of  about  the  hardness  of  carnelian, 
and  a  copper  mill  is  generally  employed  for  harder  gems.  Some 
lapidaries,  however,  prefer  a  bell-metal  mill  for  polishing  hard 
gems,  such  as  the  sapphire,  as  the  bell  metal,  being  harder  than 
the  copper,  the  mill  is  less  liable  to  be  worn  into  ridges. 

The  stone,  when  polished  on  the  back,  is  detached  from  the 
stick,  and  re-cemented  with  the  front  outwards.  The  position  of 
the  stone  requires  to  be  very  carefully  adjusted  to  make  it  exactly 


BRILLIANT    CUT.  1328 

central  and  square  with  the  stick,  or  the  front  of  the  stone 
would  be  liable  to  be  cut  oblique  to  the  back.  When  the  stone 
has  been  properly  adjusted,  the  squares  are  cut  on  the  front  of 
the  stone  exactly  as  for  fig.  1154.  The  surfaces  of  the  table  and 
squares  are  then  polished,  and  the  stone  is  detached  from  the 
stick  by  gently  warming  it  over  a  candle.  Lastly,  the  stone  is 
washed  with  turpentine  to  remove  any  small  particles  of  cement. 

The  brilliant  cut,  variously  modified,  is  the  form  of  facetting 
most  generally  adopted  for  the  fronts  of  gems  and  pastes,  and 
the  backs  of  these  stones  are  mostly  trapped,  or  cut  in  squares. 
The  principal  varieties  of  the  brilliant  cut  are  represented  in  figs. 
1157  to  1168,  in  which  every  stone  is  shown  in  three  views,  viz. 
the  plan  of  the  front  of  the  stone,  the  side  view,  and  the  plan  of 
the  back.  The  dotted  lines  around  the  upper  halves  of  the  front 
views,  are  inserted  to  show  more  distinctly  the  manner  in  which 
the  brilliant  cut,  consisting  of  lozenge-shaped  facets  alternated 
with  triangular  facets,  is  derived  from  the  square  or  trap  cut,  by 
the  removal  of  the  angles  indicated  by  the  dotted  lines. 

With  the  same  view  of  rendering  the  diagrams  more  distinct, 
the  outlines  of  nearly  all  the  girdles  are  represented  of  the 
polygonal  forms  they  would  assume,  if  the  facets  adjoining  the 
girdles  were  made  strictly  angular,  so  as  to  terminate  in  straight 
lines  upon  the  girdle.  In  the  brilliant  cut,  however,  the  girdles 
are  not  generally  cut  to  the  polygonal  forms,  but  they  are  made 
as  easy  curves,  nearly  approaching  the  forms  shown  in  the  dia- 
grams, if  the  extreme  angles  are  supposed  to  be  removed ;  and  in 
cutting  the  rows  of  facets  adjoining  the  girdles,  these  angles  are 
not  quite  developed.  The  rounded  form  of  the  girdle  is  adopted 
partially  with  the  view  of  keeping  the  stone  as  large  as  possible, 
and  avoiding  the  liability  of  the  angles  being  chipped  in  cutting 
the  facets,  and  partially  because  the  rounded  girdle  is  more 
convenient  in  setting  the  stone. 

The  size  of  the  table,  in  proportion  to  that  of  the  girdle, 
depends  in  great  measure  upon  the  thickness  of  the  stone,  com- 
pared with  its  width  or  spread,  and  the  taste  of  the  lapidary,  no 
invariable  rule  being  adopted ;  but  the  table  is  seldom  made  less 
than  half,  or  more  than  two-thirds,  the  length  of  the  girdle. 

The  size  of  the  culasse  is  very  small,  being  only  just  sufficient 
to  prevent  the  facets  at  the  back  of  the  stone  from  meeting  in  a 
point,  and  its  width  is  seldom  more  than  about  the  thirtieth  of  an 


1329 


HALF    BRILLIANT    CUT. 


inch,  although  in  large  and  long  stones  it  is  sometimes  as  much 
as  one  quarter  of  an  inch  in  length.  The  culasse  has  the  effect 
of  reflecting  a  small  quantity  of  light  into  the  table,  that  would 
otherwise  be  lost;  but  its  principal  purpose  is  to  prevent  the 
formation  of  a  weak  angle,  that  would  be  liable  to  be  easily 
broken. 

The  half  brilliant,  figs.  1157  to  1159,  is   the   most   simple 
variety  of  the  brilliant  cut,  and  is  very  generally  employed  for 


FIGS.  1157. 


1160. 


1158. 


1159. 


those  stones  that  are  too  small  to  admit  of  numerous  facets  being 
cut  upon  their  surfaces.  In  cutting  a  stone  to  the  form  of  the 
half  brilliant  the  front  is  prepared  exactly  as  for  a  single  height 
of  trapping,  the  first  step  being  to  cut  the  table ;  secondly,  the 
girdle;  and  thirdly,  the  water  basil.  The  stone  is  then  inverted  for 
cutting  the  back  ;  in  the  figure  this  is  shown  as  consisting  of  two 
rows  of  squares,  or  trapping,  with  eight  triangular  facets  cut 
upon  the  angles  of  the  eight  squares  adjoining  the  girdle;  these 
triangular  facets  are  called  under  squares,  and  are  very  generally 
employed  upon  stones  that  are  trapped  on  the  back,  partly  in 
order  to  diminish  the  size  of  the  large  squares,  and  increase  the 
number  of  facets,  and  partly  to  give  the  stone  a  more  rounded 


HALF    BRILLIANT    CUT.  1330 

figure,  by  removing  the  prominent  angles  that  would  be  liable  to 
interfere  with  the  setting. 

In  cutting  the  back,  the  stone  is  first  rounded  to  the  general 
contour ;  secondly,  the  culasse  is  cut ;  thirdly,  the  water  basil  for 
the  row  of  squares  adjoining  the  girdle;  fourthly,  the  eight  prin- 
cipal squares  are  cut  on  this  row ;  fifthly,  the  eight  squares  adjoin- 
ing the  culasse ;  and  lastly,  the  eight  under  squares,  and  the 
polishing  completes  the  back. 

The  stone  is  again  inverted  upon  the  cement  stick  for  cutting 
the  facets  on  the  front,  and  the  table  is  first  corrected,  eight 
squares  are  then  cut  upon  the  water  basil,  exactly  as  for  fig.  11 51 , 
as  represented  by  the  dotted  lines  around  the  upper  half  of 
fig.  1157  ;  and  the  surfaces  of  the  eight  planes  thus  produced, 
constitute  the  surfaces  of  the  eight  principal  planes  in  the 
finished  stone,  as  shown  in  the  figure.  These  planes  are  called 
foundation  squares,  and  are  converted  into  the  pentagonal  shape 
shown  in  the  figure,  by  cutting  one  row  of  eight  triangular  facets 
around  the  table,  and  another  row  of  eight  triangular  facets 
around  the  girdle.  The  bases  of  all  the  upper  row  of  facets 
around  the  table,  extend  from  the  center  of  the  upper  edge  of 
one  foundation  square,  to  the  center  of  the  upper  edge  of  the 
adjoining  square,  and  the  apex  touches  the  point  of  the  pentagon 
upon  the  line  of  intersection  of  the  two  squares  ;  thus  removing 
the  entire  angle  indicated  by  the  dotted  lines  in  the  figure,  and 
altering  the  position  of  the  original  octagon  constituting  the 
table  of  the  stone,  at  the  same  time  that  its  size  is  reduced  by 
the  removal  of  its  angles.  These  triangular  facets  are  called 
skill  facets,  from  the  difficulty  of  placing  them  correctly. 

The  lower  row  of  eight  facets  around  the  girdle  is  produced 
by  cutting  a  triangular  facet  upon  every  one  of  the  lower  angles 
of  the  foundation  squares,  every  lower  facet  is  placed  exactly 
opposite  the  corresponding  skill  facet,  and  is  extended  perpen- 
dicularly until  it  reaches  the  point  of  the  skill  facet ;  but,  in  the 
half  brilliant,  the  lower  row  of  facets  is  not  extended  laterally  to 
the  middle  of  the  foundation  squares,  as  this  would  remove  too 
great  an  angle,  and  diminish  the  size  of  the  stone.  The  lower 
facets  are  therefore  cut  only  so  wide  as  can  be  ventured  without 
interfering  with  the  rounded  form  of  the  girdle.  The  dotted 
lines  on  the  lower  half  of  fig.  1157  are  inserted  to  show  that  the 
lozenge  is  the  primary  form  of  the  foundation  squares  in  all  the 

VOL.  III.  X 


J331  FULL    BRILLIANT    CUT. 

varieties  of  the  brilliant  cut,  and  the  pentagonal  form  of  these 
squares  in  the  half  brilliant  arises  simply  from  the  lower  facets 
being  only  partially  developed. 

In  all  cases  of  facetting  transparent  stones,  it  is  very  important 
that  the  foundation  squares  on  the  front  should  be  equal  in 
number,  and  exactly  opposite  to  the  principal  squares  on  the 
back,  and  also  that  the  lower  facets  should  be  opposite  to  the 
under  squares,  or  otherwise  the  play  of  light  would  appear  con- 
fused, and  the  brilliancy  of  the  stone  would  be  materially 
reduced.  In  order  to  place  the  squares  opposite,  it  is  quite 
necessary  that  both  the  front  and  back  of  the  stone  should  be 
cut  accurately  with  reference  to  the  shape  of  the  girdle,  as  the 
back  of  the  stone  requires  to  be  entirely  embedded  in  the  cement 
at  the  time  the  front  is  cut ;  and  the  only  guide  employed  by  the 
lapidary  for  the  correct  position  of  the  squares,  is  derived  from 
the  general  shape  of  the  girdle,  and  the  certainty  that  the  back 
squares  have  been  correctly  placed. 

The  full  brilliant  cut  represented  in  figs.  1160  to  1162,  may 
be  received  as  the  foundation  from  which  the  other  varieties  of 
the  brilliant  cut  are  derived,  and  is  considered  to  be  the  most 
perfect  form  of  facetting  for  gems.  It  is  therefore  almost 
invariably  employed  for  all  diamonds  that  are  sufficiently  thick, 
and  perfect,  to  admit  of  its  application  ;  but  diamonds,  from 
their  crystallisation  in  the  form  of  the  octahedron,  generally 
have  a  nearly  regular  octagon  for  the  table  and  base,  instead  of 
the  irregular  octagon  selected  for  illustration.  Diamonds  cut 
into  this  form  are  called  brilliants;  and  the  term  brilliant  cut, 
when  used  alone,  is  always  understood  to  imply  that  the  front 
and  back  of  the  stone  are  both  facetted,  as  shown  in  the  figures. 
Other  gems  than  the  diamond,  and  also  pastes,  are  however 
often  facetted  in  the  same  manner  on  the  front  only,  and  the 
back  is  cut  in  some  other  mode  that  will  permit  of  a  greater 
number  of  facets  being  introduced,  generally  the  trap  cut,  or  the 
star  cut,  is  employed  on  the  back,  and  the  stone  is  then  said 
to  have  a  brilliant  cut  front,  and  a  trapped  back,  or  star-cut 
back,  as  the  case  may  be. 

In  cutting  the  full  brilliant,  the  front  of  the  stone  is  prepared 
by  cutting  the  table,  girdle,  and  water  basil,  exactly  as  for 
fig.  1151 ;  and  in  forming  the  back,  the  eight  principal  squares 
are  first  cut  just  as  in  trapping  a  single  height,  the  culasse  is 


SPLIT    BRILLIANT    CUT.  1332 

then  cut,  and  lastly,  the  16  facets  around  the  girdle,  called 
under  facets,  are  produced  by  cutting  two  triangular  facets 
upon  every  one  of  the  angles  of  the  eight  principal  squares,  which 
thus  become  converted  into  the  irregular  pentagons  shown  in  the 
figures. 

In  facetting  the  front,  the  eight  foundation  squares,  and  the 
eight  skill  facets  around  the  table,  aro  cut  in  just  the  same 
manner  as  for  the  half  brilliant ;  but  in  removing  the  lower 
angles  of  the  foundation  squares,  two  triangular  facets  are 
cut  at  every  angle,  exactly  the  same  as  on  the  back  of  the  stone. 
These  facets  are  by  some  lapidaries  called  double  skill  facets,  from 
being  cut  in  pairs,  and  by  others  brilliant  facets,  because  the  rays 
of  light  are  reflected  from  their  surfaces  with  greater  brilliancy 
than  from  any  other  part  of  the  stone. 

It  will  be  observed  that  in  the  figures  the  lozenge  shape  of  the 
foundation  squares  is  irregular,  the  lower  pair  of  sides  being 
wider  than  the  upper;  this  form  is  adopted  partly  to  allow  for  the 
small  portion  enclosed  in  the  setting  of  the  stone,  but  principally 
in  order  to  increase  the  play  of  light,  by  making  the  brilliant 
facets  as  large  as  can  be  ventured  without  materially  impairing 
the  symmetry  of  the  cutting. 

The  split  brilliant,  or  trap  brilliant,  figs.  11 63  to  11 65,  only  differs 
from  the  full  brilliant,  fig.  1161,  in  the  foundation  squares  being 
divided  horizontally  into  two  triangular  facets,  forming  an  obtuse 
angle  when  viewed  in  elevation,  as  in  fig.  1164.  In  cutting  the 
split  brilliant,  the  face  of  the  stone  is  prepared  by  forming  two 
bevels  around  the  margin,  which  are  afterwards  converted  into 
squares  exactly  like  the  stone  trapped  in  two  heights,  fig.  1153. 
The  upper  height  of  squares  is  made  narrower  than  the  lower ; 
the  skill  facets,  and  the  brilliant  facets,  are  cut  in  the  same 
manner  as  for  a  full  brilliant,  and  are  both  made  to  terminate  on 
the  ridge  dividing  the  foundation  squares  into  triangular  facets. 

The  back  of  the  stone  is  represented  as  trapped  in  three 
heights  of  different  widths,  the  narrowest  being  nearest  the 
culasse.  The  squares  of  the  trapping  are,  as  usual,  placed 
opposite  to  the  foundation  squares  on  the  front,  and  the  row  of 
squares  adjoining  the  girdle  has  its  angles  replaced  by  eight 
under  squares  placed  opposite  to  the  brilliant  facets  on  the 
front. 

The  double  brilliant,  or  Lisbon  cut,  figs.  1166  to  1168,  is  a 

x  2 


1333 


DOUBLE    BRILLIANT   CUT. 


duplication  of  the  brilliant  cut,  fig.  116  J,  having  two  rows  of 
lozenge-shaped  squares,  and  three  rows  of  triangular  facets.    The 


FIGS.  1163. 


1166. 


1164. 


\LJ 


1165. 


1168. 


two  rows  of  foundation  squares  are  first  cut  as  for  the  stone 
trapped  in  two  heights,  fig.  1153  ;  and  they  are  afterwards  con- 
verted into  the  lozenge  shape,  by  cutting  one  row  of  skill  facets 
around  the  table,  one  row  of  double  skill  facets  upon  the  angles 
joining  the  two  rows  of  squares,  and  one  row  of  brilliant  facets 
around  the  girdle.  The  dotted  lines  in  fig.  1166  show  the  angles 
removed  by  cutting  these  facets,  by  which  it  will  be  seen  that 
the  row  of  double  skill  facets  in  the  middle,  removes  at  the  one 
operation  the  inner  angles  of  both  rows  of  foundation  squares. 

In  some  few  instances  a  third  row  of  foundation  squares  is 
added,  by  first  cutting  the  stone  in  three  heights,  and  then 
cutting  three  rows  of  double  skill  facets  in  addition  to  the  row 
of  skill  facets  around  the  table ;  but  this  degree  of  elaboration 


ROSE    CUT. 


1334 


is  considered  to  cause  so  much  confusion  in  the  rays  of  light,  as 
to  entirely  neutralise  the  advantage  obtained  from  the  greater 
number  of  reflecting  surfaces,  and  is  seldom  resorted  to  except 
for  concealing  defects  in  large  stones. 

The  rose  cut  shown  in  figs.  1169  to  1173,  as  previously  men- 
tioned, is  employed  for  those  diamonds  and  other  transparent 


FIGS.  1169. 


1171. 


1173. 


1170. 


1172. 


stones  that  are  too  thin  to  admit  of  being  cut  on  the  back  ;  and 
sometimes  the  rose  cut  is  also  employed  for  opaque  stones  that 
would  derive  no  additional  lustre  from  the  back  cutting.  The 
true  rose  cut  consists  of  twenty-four  triangular  facets,  cut  upon 
a  stone  having  a  circular  or  dodecagonal  base,  flat  beneath  and 
rounded  at  the  top,  as  shown  in  fig.  1170.  The  central  portion 
of  the  stone  is  cut  into  six  equilateral  triangular  facets,  the 
points  of  which  meet  in  the  center  at  the  summit  of  the  stone, 
and  their  bases  form  a  regular  hexagon,  six  other  equilateral 
triangles  are  joined  by  their  bases  to  the  central  facets,  and 
their  points  rest  upon  the  girdle.  The  spaces  between  the  outer 
row  of  triangles  are  each  cut  into  two  triangular  facets,  which 
closely  resemble  the  double  skill  facets  in  the  brilliant  cut. 

In  cutting  the  stone,  figs.  1169  and  1170,  the  back  is  flattened, 
and  the  face  rounded  to  the  general  curve,  the  central  zone  of 
six  facets  is  then  cut,  commencing  with  two  opposite  facets,  and 
when  these  have  been  made  parallel,  and  of  the  required  size, 
the  intervals  are  each  cut  into  two  facets,  care  being  taken  that 
all  the  facets  are  of  equal  size.  The  six  principal  facets  in  the 
outer  row  are  next  cut;  and  lastly,  the  six  intervals  between 
these  facets  are  cut  into  six  pairs  of  double  skill  facets,  which 


1335 


ROSE,  SQUARE,  AND    BRILLIANT    CUTS. 


complete  the  rose  cut,  as  applied  to  diamonds,  and  thin  gems 
generally. 

Thicker  stones,  however,  are  sometimes  cut  with  an  additional 
row  of  twelve  nearly  square  facets,  arranged  around  the  outer 
row  of  triangles,  as  in  figs.  1171  and  1172;  every  square  being 
equal  in  width  to  the  base  of  its  adjoining  triangle  ;  at  other 
times,  instead  of  squares,  the  outer  row  is  composed  of  two  rows 
of  triangles. 

The  rose  cut  is  also  frequently  applied  to  elliptical  stones,  as 
in  fig.  1173 ;  and,  as  there  shown,  the  central  hexagon  is  elongated, 
and  the  triangles  are  made  of  irregular  forms. 

Figs.  1174  to  1176  represent  a  stone  cut  in  squares,  or  trapped 
in  one  height  on  both  the  front  and  back,  which  differ  from  each 
FIGS.  1174.  1177.  1180. 


other  only  in  the  greater  thickness  of  the  back,  and  the  culasse 
being  much  smaller  than  the  table.  This  form  of  cutting  is 
sometimes  adopted  for  small  crystals  and  pastes  for  cheap 
jewellery. 

Crystals  and  pastes  employed  as  fictitious  diamonds,  are  gene- 
rally cut  as  in  figs.  1177  to  1179.  The  front  is  cut  as  a  full  bril- 
liant of  eight  principal  squares,  upon  a  regular  octagonal  base 


STAR   CUT,     X     CUT,  AND    DENTAL    CUT. 


1336 


like  the  diamond.  The  back  is  first  cut  with  a  row  of  eight 
squares,  somewhat  like  fig.  1176 ;  a  row  of  double  skill  facets  are 
then  arranged  around  the  girdle,  as  in  fig.  1162  ;  and,  lastly,  a 
row  of  eight  facets  are  arranged  around  the  culasse.  These 
facets  are  cut  upon  the  angles  joining  the  principal  back  squares, 
the  points  are  extended  until  they  meet  the  double  skill  facets, 
and  the  back  facets  intersect  each  other  near  the  culasse,  giving 
the  appearance  of  a  star,  whence  this  form  of  facetting  for  the 
back  is  known  as  the  star  cut.  The  row  of  facets  around  the 
culasse  materially  increases  the  brilliancy,  and  causes  the  play  of 
light  more  nearly  to  approach  that  of  the  diamond.  Figs.  1180 
to  1182  represent  the  same  form  of  cutting  applied  to  a  hexago- 
nal stone. 

The  form  of  facetting  called  the  x  cut,  shown  in  figs.  1183  to 
1186,  is  considered  to  be  a  very  perfect  style  of  cutting  for  stones 


FIGS.  1183. 


1185. 


1187. 


1184. 


1186. 


1188. 


having  a  square  or  a  regular  octagon  for  their  base,  as  it  allows 
of  a  considerable  number  of  triangular  facets  being  cut  upon  the 
top,  and  at  the  same  time  the  table  and  girdle  may  be  retained 
of  one  regular  figure.  In  cutting  this  form,  the  front  is  trapped 
in  two  heights,  and  the  squares  thus  produced  are  converted  into 
triangles  by  cutting  one  pair  of  triangular  facets  upon  every  angle 
of  the  square  or  octagon.  As  seen  in  the  figures,  these  facets 
extend  from  the  table  to  the  girdle,  and  meet  in  the  center  of  the 
sides.  The  x  cut  is  seldom  applied  to  other  than  square  or 
octagonal  stones,  and  for  these  shapes  the  back  is  generally 
facetted  with  the  star  cut,  but  sometimes  octagonal  stones  are 
trapped  at  the  back. 

Figs.  1187  and  1188  represent  the  dental  cut,  which  consists  of 
two  rows  of  triangular  facets  cut  on  the  top  of  the  stone.     The 


1337  GENEVA    TOOL    FOR    FACETTING. 

two  rows  are  interposed,  so  that  the  bases  of  one  row  of  triangles 
form  the  margin  of  the  table,  and  the  bases  of  the  second  row 
are  placed  on  the  line  of  the  girdle,  each  row  extending  from  the 
girdle  to  the  table,  as  seen  in  the  figures,  which  show  the  appli- 
cation of  this  cut  to  an  elliptical  stone  having  eight  principal 
sides.  In  cutting  this  form,  the  front  is  first  trapped  in  one 
height  with  eight  squares,  and  the  figure  is  completed  by  cutting 
eight  triangular  facets  around  the  table,  every  facet  being  placed, 
as  usual,  upon  one  of  the  angles  formed  by  the  foundation  squares. 
The  back  is  generally  trapped. 


All  the  different  forms  of  facetting  are  usually  cut  by  practical 
lapidaries,  without  any  other  guide  than  the  gim  peg,  and  cement 
stick,  as  shown  in  fig.  1150.  The  more  difficult  cases  of  cutting 
valuable  gems,  arise  from  the  irregular  forms  of  the  rough  gems, 
or  slight  imperfections  in  their  substance,  and  these  difficulties 
require  to  be  combated  rather  by  judgment  and  dexterity  of 
hand,  than  by  mechanical  guides.  This  dexterity  once  acquired, 
renders  the  employment  of  guides  less  necessary,  when  the  forms 
of  the  rough  gems  are  more  favourable,  especially  as  the  adjust- 
ments can  be  effected  more  rapidly  by  the  practised  fingers,  than 
by  mechanical  means. 

In  the  comparatively  slow  process  of  polishing  the  facets  on 
diamonds,  a  very  simple  form  of  guide  is  adopted,  as  alluded  to 
at  page  176,  Vol.  I. ;  but  this  instrument  only  serves  to  retain  the 
stone  in  position,  and  all  the  adjustments  of  angle  are  effected 
by  hand,  in  order  that  the  operator  may  be  enabled  to  place 
every  facet  flat  upon  the  skive,  without  reference  to  the  parti- 
cular angle  at  which  it  was  cut. 


FIG.  1189. 


Fig.  1189  shows  a  modification  of  this  instrument,  contrived  by 
a  Geneva  lapidary,  to  adapt  it  to  the  cutting  of  facets  at  definite 


FICTITIOUS    GEMS.  1338 

angles,  and  published  in  the  Dictionnaire  Technologique.  The  in- 
strument, called  a  cadrans^  has  two  jaws,  «,  which  are  closed  like 
a  vice  by  a  screw  passing  through  them,  each  of  the  jaws  has  on 
the  inside  a  hemispherical  cavity,  into  which  is  fitted  a  brass  ball ; 
a  tube  passes  through  the  ball,  and  carries  at  its  upper  end  a 
small  flat  disk,  #,  having  on  the  upper  side  several  concentric 
circles  divided  into  equal  parts.  Every  circle  has  a  different 
number  of  divisions,  which  are  so  arranged  as  to  include  all  the 
numbers  usually  required  in  cutting  facets.  The  cement  stick, 
carrying  the  stone  to  be  cut,  is  made  cylindrical,  and  fits  within 
the  tube  sufficiently  tight  to  retain  its  position  during  the  cutting 
of  the  stone,  and  the  upper  end  of  the  stick  is  made  square  to 
carry  a  small  index  point,  by  which  the  divisions  on  the  disk  are 
read  off. 

The  vertical  angle  of  the  tube  is  determined  by  the  quadrant  c9 
fixed  on  one  side  of  the  jaws,  «,  and  the  tube  is  retained  at  any 
angle  by  closing  the  jaws  upon  the  ball.  The  center  of  the 
quadrant  is  supposed  to  be  in  the  center  of  the  ball,  and  the  arc 
is  divided  as  usual  into  90  degrees,  the  upper  division  is  marked  0, 
and  the  lower  70,  the  remainder  of  the  arc  being  hidden  by 
the  jaw.  When  the  tube  is  fixed  at  0,  the  cement  stick  is  vertical, 
and  this  position  serves  for  cutting  the  table  or  the  culasse  ;  on 
fixing  the  tube  at  20  degrees,  all  the  facets  cut  in  this  position 
will  be  inclined  at  that  angle,  and  the  number  of  facets  around 
the  stone  will  be  determined  by  twisting  the  cement  stick  in  the 
ibe,  until  the  index  marks  the  required  division  on  the  disk,  b. 


st; 

t 


Fictitious  gems  are  prepared  in  a  variety  of  ingenious  methods, 
metimes  stones  of  inferior  value  are  modified  in  their  colours 
y  heat,  and  substituted  for  more  valuable  gems,  as  in  the  case 
of  the  zircon,  which  is  sometimes  rendered  colourless  by  heat, 
and  substituted  for  the  diamond.  The  colours  of  carnelian 
are  principally  given  by  heat.  In  Phillip's  Mineralogy,  it  is 
stated,  that  carnelians,  when  found,  are  of  a  blackish  olive  pass- 
g  into  a  grey.  "  These  are  first  exposed  to  the  sun  for  some 
eeks,  and  then  placed  in  earthen  pots,  and  subjected  to  heat, 
which  gives  them  the  colours  which  constitute  their  value  in 
jewellery." 

Carnelian,  when  imported  into  England,  is  generally  of  a  red 


1339  STAINED    STONES,  PASTES,  METALLIC    FOILS. 

colour,  and  when  the  colour  is  too  light,  it  is  sometimes  deepened 
by  putting  it  in  an  iron  pot,  and  gradually  bringing  it  to  a  red 
heat.  Yellow  carnelian  is  by  the  same  means  rendered  red ;  but 
the  effect  of  heat  upon  white  carnelian  is  to  render  it  more 
opaque,  and  advantage  is  sometimes  taken  of  this  circumstance 
to  give  white  carnelian  the  appearance  of  the  white  onyx.  The 
various  colours  of  agates  are,  in  some  cases,  more  fully  developed 
in  the  same  manner ;  at  other  times,  the  agates  are  soaked  in  oil 
for  two  ,or  three  hours ;  the  oil  penetrates  the  agate,  and  is 
afterwards  carbonised  within  the  stone  by  exposing  the  latter  to 
the  fumes  of  heated  sulphuric  acid.  Nitrate  of  silver  is  also 
sometimes  employed  for  staining  agate,  and  other  stones. 

Pastes  are,  however,  the  most  frequent  substitutes  for  precious 
stones.  The  foundation  of  all  pastes  is  a  superior  colourless  glass 
called  strass,  made  from  very  pure  materials,  and  afterwards 
coloured  by  the  addition  of  metallic  oxides,  in  much  the  same 
manner  that  ordinary  coloured  glass  is  made,  except  that  the 
process  is  more  carefully  performed  throughout.  The  French 
are  considered  to  excel  in  the  preparation  of  pastes,  and  a  variety 
of  recipes  for  the  manufacture  of  pastes,  derived  from  various 
French  authors,  are  given  in  Dr.  lire's  "  Dictionary  of  Arts/' 
p.  943,  and  also  in  Gill's  "  Technical  Repertory,"  vol.  ii.,  p.  308. 

Metallic  foils  made  of  thin  sheet  copper  silvered  and  burnished, 
and  afterwards  coated  with  transparent  colours,  mixed  with 
isinglass  size,  are  often  employed  by  jewellers  to  improve  the 
brilliancy  of  pastes  and  inferior  stones.  The  foil  is  enclosed  in 
the  setting,  and  entirely  covers  the  back  of  the  stone,  to  which  it 
imparts  much  of  its  own  brilliancy.  When  it  is  desired  to  modify 
the  colour  of  the  stone,  a  foil  of  a  lighter  or  darker  tint  is  used, 
according  to  circumstances.  Crystals  and  pastes,  set  as  imitation 
diamonds,  generally  have  a  piece  of  silvered  foil  at  the  back. 

Painting  is  sometimes  resorted  to  for  counterfeiting  topazes, 
and  other  gems  ;  in  this  case,  a  colourless  stone,  such  as  crystal 
is  employed,  and  the  back  of  the  stone  to  be  enclosed  in  the 
setting,  is  painted  with  the  colour  removed  from  a  piece  of  foil, 
and  another  piece  of  the  same  foil  is  placed  behind  the  stone  in 
the  setting,  to  improve  the  brilliancy.  The  reflection  of  the 
colour  from  the  back  of  the  stone  is  so  uniformly  diffused 
throughout  its  substance,  that,  even  upon  close  observation,  the 
unpractised  eye  fails  to  detect  the  absence  of  colour  in  the  body 


PAINTED    STONES,  DOUBLETS,  ETC.  1340 

of  the  stone.  In  removing  the  colour  from  the  foil,  the  latter  is 
gently  warmed  over  a  candle,  and,  while  warm,  the  colour  is 
worked  up  with  a  moistened  brush,  and  immediately  applied  to 
the  stone,  care  being  taken  to  cover  every  portion  of  the  back, 
particularly  the  angles  formed  by  the  meeting  of  the  facets,  as, 
should  the  smallest  speck  remain  uncoloured,  it  would  reflect  a 
ray  of  white  light  that  would  altogether  mar  the  effect.  The 
painting  of  these  fictitious  gems  is  sometimes  so  successfully 
executed,  that  only  those  persons  thoroughly  conversant  with 
precious  stones,  are  enabled  to  distinguish  between  the  real 
gem  and  the  counterfeit,  so  long  as  the  stone  remains  in  the 
setting. 

Doublets  are  a  more  elegant  and  substantial  application  of  the 
method  of  counterfeiting  gems  by  coloured  backs,  and  trans- 
parent fronts.  In  doublets,  the  front  and  back  are  made  in  two 
pieces,  cemented  together  on  the  line  of  the  girdle.  The  front  is 
made  of  a  colourless  stone,  and  the  back  of  a  coloured  paste;  the 
two  surfaces  to  be  placed  in  contact,  are  first  ground  quite  flat 
and  smooth,  to  fit  each  other  accurately  ;  they  are  then  cemented 
together  with  a  very  thin  layer  of  clear  mastic,  and  the  doublet 
thus  prepared  is  cut  as  a  single  stone. 

In  real  gems,  advantage  is  sometimes  taken  of  the  power  of  a 
coloured  back  to  give  colour  to  a  colourless  front.  It  occa- 
sionally happens  that  a  gem  may  be  partly  colourless  and  partly 
coloured.  In  this  case,  instead  of  dividing  the  stone,  the  coloured 
portion  is  placed  at  the  back,  and,  if  possible,  the  stone  is  so 
cut  that  the  table  shall  be  parallel  to  the  imaginary  line  dividing 
the  two  portions  ;  and  if  the  stone  has  much  natural  brilliancy, 
it  is  not  imperative  that  the  coloured  portion  should  extend  to 
the  girdle,  as  a  comparatively  small  piece,  properly  placed,  will 
serve  to  colour  the  entire  stone. 

A  striking  illustration  of  this  was  recently  observed  by  the 
writer  in  the  case  of  a  sapphire,  the  bulk  of  which  was  perfectly 
colourless,  and  a  small  part  only  of  a  deep  blue  colour.  This 
gem  was  about  one-sixth  of  an  inch  in  length,  and  nearly  of  the 
same  measure  from  the  table  to  the  culasse,  the  great  propor- 
tional depth  having  been  adopted,  in  order  that  the  colour  might 
be  reflected  throughout  the  body  of  the  stone,  from  the  small 
blue  portion,  which  was  scarcely  larger  than  the  head  of  an 
ordinary  pin,  and  yet  in  consequence  of  its  being  situated  exactly 


1341  LAPIDARY    APPARATUS    FOR    AMATEURS. 

upon  the  culasse,  and  extending  a  small  distance  up  the  back 
facets,  the  blue  colour  appeared  to  be  uniformly  diffused  through- 
out the  stone  when  viewed  from  the  front,  although  at  the  time 
of  inspection  the  stone  was  not  set.  When  viewed  from  the 
back,  the  body  of  the  stone  appeared  quite  colourless,  with  a 
small  speck  of  a  dark  blue  colour  on  the  culasse. 

Some  management  is,  however,  required  to  obtain  this  result, 
as,  if  the  stone  have  too  much  width  or  spread,  the  edges  will 
appear  colourless,  and  in  extreme  cases  the  blue  w7ill  only  show 
as  a  dark  central  speck.  Owing  to  the  various  degrees  of  bril- 
liancy in  different  stones,  and  the  variation  in  the  size  of  the 
coloured  portion,  no  invariable  rule  can  be  adopted  for  the 
spread  of  the  stone  relatively  to  the  depth  ;  the  proportions  are 
therefore  obtained  by  trial,  the  spread  being  gradually  reduced 
without  interfering  with  the  thickness,  until  the  desired  result  is 
obtained. 


SECT.    III. LAPIDARY    APPARATUS    FOR    AMATEURS. 

LAPIDARY  apparatus  for  amateurs  is  in  some  cases  made  pre- 
cisely similar  to  that  described  in  the  preceding  section,  but  more 
generally  the  laps  are  driven  by  a  foot  wheel  and  treadle  ;  the 
general  arrangement  of  the  apparatus  then  closely  resembles  the 
horizontal  grinding  machine  shown  in  fig.  1039,  page  1157,  in 
which  the  upper  surface  of  the  lap  is  not  obstructed  by  a  ver- 
tical spindle,  as  in  the  lapidary's  bench,  fig.  1141,  and  the  same 
spindle  is  employed  for  all  the  different  grinding  and  polishing 
wheels. 

The  less  difficult  process  of  lapidary  work,  such  as  producing 
a  flat  or  a  rounded  surface  on  a  pebble,  may  be  executed  with 
facility  on  the  horizontal  grinding  machine,  which  is  frequently 
converted  into  a  simple  lapidary  apparatus  by  the  addition  of  a 
slicer  and  trough  to  catch  the  water  thrown  off  the  lap.  But  for 
the  more  elaborate  processes  of  lapidary  work,  such  as  cutting  a 
stone  into  thin  slices  and  facetting  gems,  other  additions  have 
been  made,  in  which  the  principal  difficulties  of  manipulation  are 
removed  by  the  introduction  of  guides  for  slitting  and  facetting, 
and  the  apparatus  then  assumes  the  more  complete  forms  shown 
in  figs.  1190  and  1192. 

Fig.  1190  represents  the  amateur  lapidary   apparatus   fitted 


CRANE    FOR    SLICING    STONES. 


1342 


with  the  crane,  or  swinging  arm,  for  presenting  the  stones  to 
the  slicer.  The  foundation  of  the  apparatus  exactly  resembles 
that  described  in  page  1157,  except  that  the  rectangular  trough, 
indicated  by  the  dotted  lines  in  fig.  1190,  occupies  the  place 
of  the  upper  platform  in  fig.  1139,  and  the  lower  platform 

FIGS.  1190. 


has  an  enlargement  at  its  right-hand  corner  for  the  support  of  a 
strong  cylindrical  pillar  that  carries  the  socket  a ;  this  socket 
slides  vertically  upon  the  pillar,  and  admits  of  being  fixed  at  any 
height  by  means  of  the  binding  screws  b  b.  The  swinging  arm,  c, 
is  supported  on  the  socket  by  two  center  screws,  one  of  which  is 
seen  at  d ;  these  center  screws  allow  of  the  horizontal  motion  of 
the  arm,  which  has  near  the  front  a  rectangular  opening,  in 
which  is  fitted  a  ball  and  socket-joint ;  and  a  binding  screw  at 
the  extremity  of  the  arm  serves  to  retain  the  ball  at  any  desired 
angle. 

The  ball  is  perforated  with  a  square  hole,  into  which  is  fitted 
the  square  stem  of  a  metal  cup,  for  the  reception  of  the  stone  to 
be  sliced.  The  cup  and  ball  are  shown  separately  in  fig.  1191 ; 
and,  as  there  seen,  the  stem  of  the  cup  passes  through  the  ball, 
and  is  fixed  by  the  milled  nut  beneath.  The  arm  is  drawn 
towards  the  slicer  by  the  weight  e,  a  line  from  which  passes  over 


1343  APPARATUS  FOR  CUTTING  FACETS. 

the  pulley  fr  fixed  on  the  end  of  the  frame,  and  is  attached  to  a 
small  stud  screwed  into  the  under  side  of  the  arm. 

In  slitting  a  stone  with  this  apparatus,  it  is  first  cemented  in  a 
cup  of  appropriate  size,  the  stone  and  cup  being  both  heated 
nearly  to  the  fusing  point  of  the  cement.  The  stone  is  placed 
with  the  intended  line  of  division  as  nearly  horizontal  as  conve- 
nient, and  when  the  cement  is  set,  the  cup  is  inserted  in  the  ball 
and  fixed  by  the  milled  nut.  The  position  of  the  ball  is  then 
adjusted  until  the  line  of  division  is  exactly  horizontal,  and  the 
precise  height  is  regulated  by  sliding  the  socket  upon  the  vertical 
pillar.  When  the  adjustments  have  all  been  satisfactorily  made, 
the  binding  screws  are  tightened,  and  the  weight  is  attached  to 
the  line;  this  completes  the  preparations  so  far  as  the  adjustment 
of  the  apparatus  is  concerned  ;  and  when  one  cut  has  been  made, 
if  the  stone  is  required  to  be  cut  into  parallel  slices,  it  is  only 
necessary  between  every  cut  to  shift  the  socket  ff,  upwards,  a 
distance  equal  to  the  thickness  of  the  intended  slice. 

Of  course  the  slicer  requires  to  be  charged  with  diamond 
powder,  and  lubricated  with  the  oil  of  brick,  as  explained  at 
page  1310;  and  the  weight  should  also  be  proportioned  to  the 
size  of  the  stone.  To  allow  of  the  ready  adjustment  of  the 
weight,  it  is  made  in  detached  disks,  with  central  holes  that  fit 
upon  a  cylindrical  rod,  to  which  the  line  is  attached.  The  rod  is 
flattened  near  its  upper  end,  and  every  disk  has  a  radial  mortise 
extending  from  the  central  hole  to  the  edge.  In  applying  the 
weight,  the  mortise  is  passed  over  the  flattened  part  of  the  rod, 
and  the  central  hole  is  slipped  down  the  cylindrical  portion  of 
the  rod,  which  is  too  large  to  pass  through  the  mortise. 

In  fig.  1192  the  apparatus  for  cutting  facets  is  represented, 
the  upright  pillar  at  the  back  is  here  employed  to  support  the 
platform  <?,  and  upon  this  is  mounted  the  gim  peg  A,  which  may 
be  employed  for  cutting  facets  in  the  same  manner  as  that  used 
by  practical  lapidaries ;  but  the  instrument  for  cutting  facets 
shown  at  /,  is  a  more  exact  contrivance,  and  far  better  adapted 
for  the  purposes  of  the  amateur,  as  the  facets  may  be  cut  to  any 
required  angle  with  great  exactness,  and  the  operator  has  only 
to  determine  the  size  of  the  facets  by  suspending  the  process 
when  each  facet  is  sufficiently  developed. 

The  basis  of  the  instrument  is  exactly  the  same  as  those  for 
setting  straight  and  angular  turning  tools,  shown  in  fig.  1042, 


INSTRUMENT    FOR    CUTTING    FACETS. 


1344 


p.  1159,  and  fig.  1047,  p.  1165;  indeed  the  same  instru- 
ment may  be  made  to  serve  all  three  purposes  when  fitted  with 
suitable  beds  or  sockets  for  the  reception  of  the  different  objects 
to  be  ground.  In  the  instrument  for  grinding  facets  the  bed 
g,  shown  in  fig.  1042,  is  replaced  by  a  frame,  which  is  mounted 


FIGS.  1192. 


in  the  same  manner,  and  is  therefore  capable  of  being  set  to  any 
angle,  either  vertical  or  horizontal. 

The  frame,  shown  separately  on  a  larger  scale  in  fig.  1194, 
carries  a  steel  spindle,  which  is  capable  of  revolving  within 
bearings,  and  may  be  fixed  at  any  position  by  the  binding 
screw,  n.  A  hole  bored  up  the  center  of  the  spindle  extends  nearly 
through  its  length,  and  into  this  is  fitted  the  cylindrical  stem  of 
the  cement  cup,  p,  intended  for  the  reception  of  the  stone.  The 
cement  cup  is  retained  in  the  spindle  by  the  small  binding 
screw,  q.  For  determining  the  position  of  the  spindle,  a  small 
pulley,  r,  is  fixed  on  its  front  end  ;  the  edge  of  the  pulley  is  pro- 
vided with  two  circles  of  graduations,  the  one  containing  96 
divisions,  the  other  60  ;  and  to  enable  the  divisions  to  be  read 
off  with  accuracy,  an  index  is  fixed  on  the  top  of  the  frame. 


1345 


INSTRUMENT    FOR    CUTTING    FACETS. 


The  annexed  table  shows  the  divisions  of  the  circle  that  may 
be  obtained  from  the  two  circles  of  96  and  60,  which  will  be 
found  sufficient  for  general  purposes. 


In  2 

parts  by 

48  in 

96 

In    8 

parts  by  12 

in 

96 

In 

20  parts 

by  3 

in  60 

»   3 

32    „ 

96 

„  10 

„          6 

,? 

60 

5> 

24         „ 

4 

„   96 

M      4 

24   „ 

96 

„  12 

»           8 

w 

96 

>5 

30         „ 

2 

„   60 

12   „ 

60 

„  15 

„           4 

»» 

60 

)» 

32         „ 

3 

„   96 

"   6 

16    „ 

96 

„  16 

6 

n 

96 

}J 

48         „ 

2 

»   96 

The  first  column  contains  the  number  to  be  obtained ;  the 
second,  the  number  of  divisions  to  be  taken  in  the  circle  denoted 
by  the  third  column.  In  cases  where  the  same  intersection 
could  be  obtained  in  both  circles,  the  lowest  has  been  selected 
for  easy  reading. 

In  some  cases,  instead  of  the  divisions  and  index,  a  toothed 
wheel  and  click  are  adopted ;  but  this  arrangement  gives  fewer 


FIG.  1194. 


divisions  of  the  circle,  as  the  choice  is  confined  to  the  intersec- 
tions in  the  number  of  teeth  in  the  wheel.  A  much  greater 
range  is  obtained  by  a  worm  wheel  and  tangent  screw ;  but  this 
arrangement  is  more  tedious,  and  is  scarcely  called  for  in  cutting 
facets. 

In  facetting  a  stone  with  the  arrangement  fig.  1192,  the  stone 
is  prepared  by  cutting  it  to  the  general  contour  by  hand,  in  the 
same  manner  as  practised  by  lapidaries,  the  stone  being  fixed 
upon  an  ordinary  cement  stick,  the  flat  surface  for  the  table  is 
first  cut,  and  then  the  girdle.  The  front  and  back  of  the  stone 
are  afterwards  rounded  nearly  to  the  required  shape,  and  water 
basils  cut,  to  denote  the  width  of  the  principal  facets.  The 


INSTRUMENT    FOR    CUTTING    FACETS.  1346 

stone  is  then  removed  from  the  cement  stick,  and  attached  to 
the  cup  jt?,  shown  in  fig.  1194,  in  the  same  manner  that  it 
was  previously  attached  to  the  cement  stick ;  but  it  is  here  of 
still  greater  importance  that  the  stone  should  be  placed  exactly 
in  the  center  of  the  cup,  and  quite  horizontal ;  or,  otherwise, 
the  facets  will  be  cut  at  irregular  angles. 

To  assist  in  determining  the  position  of  the  stone  before  it  is 
finally  cemented,  it  will  be  found  convenient,  after  the  cement 
has  been  attached  to  the  cup,  to  press  the  cold  stone  into  the 
cement,  while  the  latter  is  still  warm  and  soft.  This  serves  to 
form  the  cement  correctly  to  the  shape  of  the  stone,  and  permits 
the  position  of  the  latter  to  be  more  deliberately  inspected,  and, 
if  necessary,  corrected.  When  the  position  of  the  stone  is 
found  to  be  satisfactory,  the  stone  may  be  warmed  over  the 
candle,  and  the  surface  of  the  cement  fused  just  sufficiently  to 
adhere  to  the  stone,  which  may  then  be  slightly  pressed  into  the 
cavity;  the  cement  is  lastly  worked  into  the  angles  with  the 
fingers,  which  may  be  slightly  moistened,  to  prevent  the  adhesion 
of  the  cement, 

The  stone  is  attached  to  the  instrument  by  sliding  the  stem  of 
the  cement  cup  p,  into  the  socket,  as  seen  in  1194,  and  fixing  it 
by  the  small  binding  screw  q.  The  projection  of  the  stone  from 
the  socket  of  the  instrument  should  be  so  adjusted  that  the  socket 
may  be  exactly  vertical,  when  the  plane,  C,  fig.  1047,  p.  1165,  is 
fixed  at  0,  on  the  graduated  arc,  B,  and  the  face  of  the  stone 
rests  upon  the  lap,  while  the  feet  of  the  instrument  are  supported 
upon  the  platform.  The  correct  position  of  the  instrument  is 
most  readily  estimated,  by  observing  that  the  base  piece,  A,  is 
parallel  to  the  platform. 

With  large  stones,  it  will  sometimes  be  found  desirable  to 
effect  the  adjustment  by  elevating  or  depressing  the  platform, 
instead  of  adjusting  the  projection  of  the  cement  cup  ;  but  with 
small  stones,  it  will  be  generally  found  more  convenient  to  place 
the  platform  level  with  the  surface  of  the  lap,  under  the  test  of 
a  straight  edge,  in  order  that  no  after-adjustment  of  the  instru- 
ment may  be  required  when  the  laps  are  exchanged  for  smoothing 
and  polishing. 

The  facets  are  cut  in  the  same  order  that  is  adopted  in 
cutting  corresponding  forms  with  the  gim  peg,  and  which  has 
been  already  explained  in  the  second  section ;  but  the  vertical 

VOL.  III.  Y 


1347  INSTRUMENT    FOR    CUTTING    FACETS. 

nclination  for  every  row  of  facets  is  obtained  by  adjusting  the 
plane  C,  shown  in  fig.  1047,  p.  1165,  upon  the  graduated  arc  B, 
and  the  number  of  facets  in  every  row  is  determined  by  the 
divisions  on  the  pulley  of  the  socket  shown  in  fig.  1194. 

Thus,  in  cutting  a  stone  with  a  brilliant-cut  front,  and  a  star- 
cut  back,  like  fig.  1 178,  the  plane  C  is  placed  at  0,  on  the  arc  B, 
for  cutting  the  culasse.  The  principal  row  of  eight  squares  at  the 
back  is  cut  with  the  plane,  C,  inclined  to  about  50,  and  the  socket 
is  fixed  successively  at  the  divisions  12,  24,  36,  48,  60,  72,  84, 
and  96.  The  row  of  16  double  skill  facets  around  the  girdle  is 
cut  with  the  plane,  C,  inclined  to  about  45,  and  the  divisions 
employed  are  3,  9,  15,  21,  and  so  on  to  93,  in  order  that  the 
double  skill  facets  may  terminate  upon  the  angles  of  the  prin- 
cipal squares.  The  row  of  eight  facets  around  the  culasse  are 
cut  with  the  plane,  C,  inclined  to  about  55,  and  the  socket  is 
fixed  at  the  divisions  6,  18,  30,  42,  &c.,  a  facet  being  cut  at 
every  twelfth  division,  as  in  the  row  of  primary  squares  ;  but, 
in  order  that  the  two  rows  of  facets  may  be  interposed,  the 
intermediate  numbers  are  employed.  In  cutting  the  front  of 
the  stone,  the  same  series  of  divisions  are  employed  for  deter- 
mining the  numbers  of  facets,  and  the  vertical  angles  are,  0,  for 
the  table ;  50  for  the  foundation  squares ;  40  for  the  skill  facets ; 
and  60  for  the  brilliant  facets. 

Fig.  1193  represents  a  supplementary  spindle  that  is  screwed 
on  the  end  of  the  upright  mandrel,  and  is  employed  for  carrying 
small  mills  and  balls,  which  are  held  by  a  plain  conical  fitting, 
and  employed  for  cutting  mouldings  and  other  details,  as  men- 
tioned at  page  1318. 


CHAPTER  XXXV. 

GEM  AND  GLASS  ENGRAVING. 

SECT.    I. INTRODUCTION. SEAL    AND    GEM    ENGRAVING. 

GEMS,  precious  stones,  glass,  and  similar  hard  substances  that 
do  not  admit  of  the  application  of  tools  with  cutting  edges,  are 
engraved  either  in  relief,  or  in  intaglio,  by  the  employment  of 
small  revolving  wheels,  charged  on  their  edges  with  fine  abrasive 
powders,  and  lubricated  with  oil  or  water.  The  object  to  be 
engraved  is  applied  to  the  lower  edges  of  the  wheels  with  the 
fingers,  unassisted  by  any  mechanism,  but  the  object  is  twisted 
about  during  the  process,  so  as  to  expose  every  part  of  the 
device  successively  to  the  action  of  the  little  wheels,  which 
gradually  produce  small  hollows  and  grooves,  that  are  in  section 
nearly  counterparts  of  the  sections  of  the  tools  employed  in  their 
formation.  The  wheels  are  made  in  a  great  variety  of  sizes  and 
shapes,  according  to  the  forms  they  are  intended  respectively  to 
produce,  and  with  the  abrasive  powders  they  constitute  the  only 
cutting  tools  applied  in  these  interesting  and  delicate  processes 
of  abrasion. 

For  engraving  all  hard  stones,  the  wheels  are  made  of  iron, 
charged  with  diamond  powder,  and  generally  lubricated  with 
the  oil  of  bricks,  and  when  the  engraved  surfaces  are  polished, 
copper  wheels  charged  with  rottenstone  and  water  are  employed. 
For  engraving  glass,  similar  but  larger  tools  made  of  copper, 
charged  with  emery  and  olive  oil,  are  employed,  and  the  polish- 
ing  is  effected  with  leaden  tools  charged  with  pumice  stone 
powder  and  water.  The  processes  of  engraving  in  gems  and 
glass  are  very  similar,  and  differ  principally  in  the  greater  depth 
and  elaboration  of  the  designs  in  gem  engraving,  which  latter 
will  be  first  described,  and  the  principal  peculiarities  of  glass 
engraving  will  be  afterwards  alluded  to  in  a  separate  section. 

y2 


1349  SEAL  ENGRAVER'S  ENGINE. 

The  most  extensive  application  of  engraving  on  stones,  is  the 
sinking  in  intaglio  of  armorial  bearings  on  seals,  which  is  called 
seal  engraving,  and  the  engraving  in  intaglio  of  more  artistic 
subjects  on  gems  and  stones  is  called  gem  engraving.  When 
the  design  is  engraved  in  relief,  the  process  is  called  cameo 
cutting,  but  the  apparatus  and  manipulations  are  nearly  the 
same  in  all  three  branches  of  the  art.  The  ordinary  practice  of 
seal  engraving  will  be,  therefore,  first  described,  followed  by 
some  observations  on  the  more  graceful  art  of  gem  engraving, 
and  the  practice  of  cameo  cutting  will  be  afterwards  adverted  to. 

The  greater  portion  of  the  remarks  offered  on  seal  engraving 
have  been  gathered  from  the  practice  of  Mr.  W.  Warner,  who 
has  had  considerable  experience  in  engraving  armorial  bearings 
both  in  hard  and  soft  stones.  The  observations  on  gem  engrav- 
ing and  cameo  cutting  have  been  derived  from  Mr.  Henry 
Weigall,  whose  works  in  these  arts  have  obtained  a  celebrity 
that  is  a  satisfactory  guarantee  for  the  excellence  of  his  practice, 
and  to  whom  the  contents  of  the  first  two  sections  of  this 
chapter  have  been  submitted  for  verification. 


The  wheels  employed  in  seal  engraving  are  called  tools,  and 
are  made  as  shown  in  fig.  1206,  with  long  conical  stems  that  are 
fitted  somewhat  like  chucks  into  the  hollow  mandrel  or  quill  of  a 
miniature  lathe  head,  called  a  seal  engraver's  engine,  the  most 
usual  form  of  which  is  shown  one-fourth  of  its  real  size  in  fig.  1196, 
this  is  mounted  upon  a  stout  table  hollowed  out  in  front  some- 
what like  a  jeweller's  bench,  and  either  about  2  feet  6  inches  or 
3  feet  6  inches  high,  according  as  the  operator  may  prefer  to  sit 
or  stand  to  his  work.  The  engine  is  driven  by  a  light  foot  wheel 
from  18  inches  to  2  feet  diameter.  The  tools  being  of  very 
small  diameter,  little  power  is  required  ;  a  rapid  motion  is,  how- 
ever, requisite  for  some  parts  of  the  work,  and  a  steady  position 
of  the  body  is  at  all  times  of  the  first  importance ;  the  treadle 
is,  therefore,  jointed  just  beneath  the  heel  of  the  operator,  who 
is  thus  enabled  to  give  a  rapid  motion  to  the  wheel  with  but 
little  movement  of  the  leg.  The  entire  apparatus  should  be  quite 
free  from  tremor,  and  with  this  view  the  bench  is  made  very 
strong,  and,  if  possible,  firmly  attached  to  the  building.  In 
some  cases  the  foot  wheel  is  mounted  in  a  frame  independent  of 


SEAL    ENGRAVERS    ENGINE. 


1350 


the  bench,  in  order  that  any  vibration  in  the  wheel  or  its  axis 
may  not  be  communicated  to  the  tools. 

Fig.  1195,  shows  the  section  of  the  engine,  which  consists  of  a 
brass  pillar  about  6  inches  high,  having  at  the  base  a  central 


FIGS.  1195. 


1196. 


1197. 


bolt,  which  passes  through  the  top  of  the  bench,  and  is  retained 
by  a  nut  and  washer  beneath.  The  upper  part  of  the  pillar  has 
two  openings,  which  cross  each  other  at  right  angles,  and  serve 
for  the  reception  of  the  pulley  and  bearings  of  the  quill.  The 
bearings  are  generally  cylindrical,  and  made  of  tin  or  pewter 
cast  upon  the  quill ;  each  pair  of  bearings  is  adjusted  to  fit  the 
quill  by  a  set  screw,  passing  through  a  brass  cap  screwed  on  the 
top  of  the  pillar.  The  quill  is  of  steel,  about  2  inches  long,  and 
half  an  inch  diameter ;  it  passes  entirely  through  the  bearings, 
all  end-play  in  which  is  prevented  by  two  small  beads  upon  the 
quill. 

Throughout  the  length  of  the  quill  extends  a  slightly  conical 
hole,  measuring  about  five-sixteenths  of  an  inch  in  diameter  at 
the  front  end,  and  one  quarter  of  an  inch  at  the  back.  A  small 
angular  groove,  about  half  an  inch  long,  is  filed  in  one  side  of  the 


1351  SEAL  ENGRAVER'S  TOOLS. 

hole,  at  the  front  end,  for  the  reception  of  a  corresponding 
feather  on  the  tools,  which  serves  to  prevent  the  tools  from 
slipping  round  in  use,  and  also  to  ensure  their  being  always 
placed  in  the  same  position  in  the  quill.  The  pulley,  which 
measures  about  one  inch  and  a  half  in  diameter,  is  mostly  made 
in  the  same  piece  with  the  quill,  and  when  in  its  place  is  almost 
concealed  in  the  upper  part  of  the  pillar.  A  small  hemispherical 
cap  is  fitted  on  the  top  of  the  pillar,  to  exclude  all  dust  or  grit 
from  the  bearings,  and  it  is  also  very  generally  used  as  a  rest  for 
steadying  the  hand  during  the  process  of  engraving. 

In  some  cases  the  quill  is  made  3  or  4  inches  long,  and 
mounted,  more  like  an  ordinary  lathe  mandrel,  in  a  conical  steel 
collar  at  the  front,  and  a  back  center  also  of  steel.  In  this  case 
the  conical  hole  for  the  tools  extends  about  2  inches  up  the  quill, 
and  a  central  mortise  is  made  at  the  bottom  of  the  hole,  for  the 
insertion  of  a  lever  or  wedge,  by  which  the  tools  are  forced  out, 
or  otherwise  a  collar  is  cast  upon  the  front  end  of  the  tools,  and 
they  are  released  with  a  forked  lever. 

The  tools  are  made  of  iron  wire,  prepared  from  the  softest  stub 
iron,  and  carefully  annealed,  to  render  them  as  soft  as  possible. 
The  conical  plug  that  fits  into  the  quill  of  the  engine,  is  formed 
by  casting  around  the  stem  of  the  tool  a  corresponding  cone  of 
some  easily  fused  metal,  as  tin,  pewter,  or  lead  hardened  with  a 
little  antimony.  The  moulds  for  casting  the  conical  plugs  are 
made  in  various  forms,  but  the  general  construction  will  be  suffi- 
ciently obvious  from  an  inspection  of  the  section  shown  in 
fig.  1198,  in  which  a  represents  the  body  of  the  mould  in  which 
the  plug  is  cast ;  #,  the  metal  socket  in  which  the  tool  and  mould 
are  fixed  to  retain  them  both  central ;  and  c,  the  wooden  block 
for  the  support  of  the  whole.  The  part  a  is  made  a  little  longer 
than  the  quill,  and  is  fitted  in  the  middle  of  its  length  with  a 
stem  and  wooden  handle,  which  give  it  somewhat  the  appearance 
of  a  hammer.  Throughout  its  length  extends  a  central  conical 
hole,  the  angle  of  which  is  exactly  a  copy  of  that  in  the  quill, 
(both  holes  being  generally  formed  with  the  same  tools,)  and  at 
the  larger  end  of  the  hole  is  filed  an  angular  groove  to  form  a 
feather  to  fit  in  the  corresponding  groove  in  the  quill.  The  end 
of  the  mould  «,  having  the  groove,  has  a  short  cylindrical  neck 
turned  on  the  outside,  and  concentric  with  the  hole,  and  this 
neck  is  fitted  into  a  corresponding  recess  in  the  upper  part  of 


SEAL  ENGRAVER'S  TOOLS.  1352 

the  socket  b.  The  socket  is  made  in  halves,  fitted  together  with 
steady  pins,  and  has  a  central  hole  for  the  reception  of  the  tools. 
The  exterior  of  the  socket  is  made  rather  conical  and  fits  into  a 
corresponding  hole  in  the  wooden  block  c. 

In  preparing  the  tools  after  the  wire  has  been  annealed,  they 
are  first  roughly  filed  into  form,  the  small  disks  are  filed  out  of 
the  solid,  the  stem  that  projects  from  the  end  of  the  quill  is 
made  round,  rather  conical,  and  a  little  smaller  at  the  largest 
part,  than  the  hole  in  the  socket.  The  shank  that  is  to  have 
the  conical  plug  cast  upon  it  is  made  square,  slightly  taper,  and 
with  a  few  notches  roughly  filed  in  the  angles,  in  order  that  it 
may  be  firmly  held  in  the  casting.  The  socket  b  is  then  sepa- 
rated, and  the  stem  of  the  tool  is  made  to  fit  the  central  hole, 
rather  tightly,  by  winding  a  slip  of  paper  around  it.  The  socket 
is  then  closed,  inserted  in  the  wooden  block,  and  pressed  tightly 
down,  when  the  conical  form  of  the  exterior  of  the  socket  and  of 
the  hole,  ensure  a  firm  grasp  upon  the  stem  of  the  tool. 

The  mould  a  is  then  fitted  into  the  recess  in  the  socket  &, 
which  ensures  the  square  stem  of  the  tool  being  central  with  the 
conical  hole,  and  the  fluid  metal  is  poured  in  from  a  small  ladle. 
When  the  metal  is  set,  the  socket  is  removed  from  the  block 
and  separated,  any  superfluous  metal  that  may  have  lodged  on 
the  upper  end  of  the  mould  is  filed  off,  the  tool  is  then  pushed 
out  of  the  mould,  and  is  ready  to  be  inserted  in  the  quill. 

It  is  of  primary  importance  that  the  tools  should  run  per- 
fectly true  in  the  engine,  and  therefore  after  the  plugs  have  been 
cast,  the  tools  are  fixed  in  the  quill,  and  turned  to  the  required 
forms,  with  small  gravers  applied  in  the  usual  manner.  The 
rest  for  turning  the  tools  is  shown  in  fig.  1197,  and  much 
resembles  that  employed  in  the  turnbench  of  the  watchmaker ; 
when  in  use  the  horizontal  bar  is  passed  through  the  mortise 
in  the  brass  standard,  and  retained  in  its  position  by  a  binding 
screw. 

The  forms  and  sizes  of  the  tools  employed  in  seal  engraving 
very  numerous,  to  adapt  them  to  the  various  parts  of  the 
ifferent  devices,  but  the  general  shape  is  that  of  little  disks 

ore  or  less  rounded  on  the  edges,  which  is  the  part  almost 
exclusively  used.  Some  of  the  tools  for  cutting  fine  lines  are 
made  almost  as  thin  on  the  edge  as  a  knife,  others  rather  thicker 
and  more  rounded  on  the  edge,  are  employed  for  thicker  lines. 


1353 


SEAL    ENGRAVER  S    TOOLS. 


For  sinking  large  shields,  and  similar  purposes,  the  tools  are 
considerably  rounded,  being  in  some  cases  made  almost  spheri- 
cal, as  a  tool  with  a  rounded  edge  is  found  to  cut  more  rapidly 
than  one  with  a  more  nearly  flat  edge ;  and,  therefore,  a  rounded 
tool  is  generally  used  for  removing  the  principal  bulk  of  the 
material  in  large  works,  and  a  tool  with  a  flatter  edge  is  used  for 
smoothing  the  surface.  For  flat  surfaces,  the  tools  are  of  course 
made  with  flat  edges,  and  to  enable  them  to  be  applied  to  deep 
works  without  the  stem  interfering  with  their  action,  the 
diameter  of  the  front  of  the  tool  is  generally  made  somewhat 
smaller  than  the  back,  so  as  to  make  the  edge  rather  conical,  as 
seen  in  fig.  1202. 

Figs.  1199  to  1205,  represent  some  of  the  most  usual  shapes 


FIGS.  11 99. 


1200. 


1201. 


1202. 


1203. 


1204. 


1205. 


120G. 


of  tools,  but  the  sizes  are  greatly  magnified  for  distinctness,  th( 
tools  shown  in  figs.  1199  to  1202,  being  seldom  larger  than  on< 
sixth  of  an  inch  in  diameter,  and  tools  of  nearly  all  the  shaj 
are  made  very  much  smaller  than  that  size,  some  of  them  beii 
made  so  small  as  not  to  exceed  the  TJ-o-th  of  an  inch  in  diamel 
and  can  hardly  be  distinguished  by  the  naked  eye  from  the 
of  the  tool,  which  appears  to  terminate  almost  in  a  needle  poii 


CHARGING   THE   TOOLS   WITH    DIAMOND    POWDER.  1354 

although  on  examination  with  a  powerful  magnifier  the  disks  are 
distinctly  developed.  The  general  form  of  the  point  of  these 
minute  tools  is  shown  in  fig.  1207,  which  represents  the  disk  and 
part  of  the  stem  magnified  about  fifteen  times. 

These  exceedingly  minute  tools  do  not  admit  of  being  formed 
of  so  small  a  size  by  the  turning  tool  alone,  they  are  therefore 
reduced  as  small  as  possible  with  a  fine  file,  and  are  afterwards 
employed  for  works  of  a  little  larger  size,  until  they  become  suffi- 
ciently small  to  be  used  for  making  very  minute  dots,  such  as 
sometimes  occur  in  the  markings  of  the  eyes,  in  figures  of  men 
or  animals,  the  full  lengths  of  which  do  not  exceed  one  quarter 
of  an  inch. 

All  the  tools  are  required  to  have  tolerably  smooth  surfaces, 
and  to  be  quite  free  from  ridges  or  hollows.  In  use  they  are 
liable  to  be  worn  into  minute  hollows,  which  are  called  creases, 
and  should  one  of  these  be  formed  in  the  side  of  a  thin  tool,  such 
as  fig.  1199  or  1201,  it  would  be  almost  certain  to  chip  off  a  frag- 
ment of  the  stone,  as  soon  as  the  crease  was  embedded  in  the 
cut.  To  prevent  the  formation  of  creases  in  thin  tools,  the  seal 
engraver  makes  frequent  use  of  a  fine  file  to  smoothen  the  sides 
of  the  tool,  and  which  at  the  same  time  serves  to  prevent  the 
edge  of  the  tool  from  becoming  thickened  as  it  is  reduced  in 
diameter  by  wear. 

The  tools  are  charged  with  fine  diamond  powder,  prepared  as 
described  in  page  1052,  in  the  mortars  shown  in  figs.  1 142  to 
1144,  p.  1309.  Seal  engravers  generally  keep  the  diamond 
powder  in  the  mortar  in  which  it  was  ground  ;  the  powder  is 
mixed  into  a  pasty  condition  with  olive  oil,  and  small  quantities 
are  taken  out  as  required.  Sometimes  the  diamond  powder,  or 
paste,  is  kept  in  small  quantities  in  a  little  conical  cup,  and  the 
diamond  is  supplied  to  the  tool,  either  by  holding  the  cup  to 
the  tool,  or  a  little  of  the  diamond  powder  is  removed  with  a 
small  spatula,  and  held  to  the  edge  of  the  tool. 

More  generally,  however,  the  seal  engraver  wears  on  the  fore- 
finger of  the  right  hand,  a  ring  made  of  a  strip  of  tin,  to  which 
are  soldered  two  little  hollow  disks,  about  half  an  inch  in  dia- 
meter, one  of  which  contains  a  very  small  quantity  of  the  diamond 
paste,  the  other,  one  or  two  drops  of  the  oil  of  bricks.  The 
diamond  paste  is  occasionally  applied  to  the  extreme  edge  of  the 
tool  while  it  is  revolving  slowly,  the  tool  is  then  moistened  with 


1355  SEAL    ENGRAVING PREPARING    THE    STONES. 

the  oil  of  bricks,  and  the  cutting  is  proceeded  with,  until  the 
brick  oil  is  nearly  expended,  when  the  tool  is  again  moistened. 
Should  the  tool  be  allowed  to  become  too  dry,  the  diamond 
would  become  detached  from  the  tool,  and  instead  of  the  stone 
being  cut,  the  tool  itself  would  be  abraded,  and  as  the  brick  oil 
is  very  volatile,  it  requires  to  be  frequently  applied.  Some 
artists  prefer  sperm  oil  for  lubricating  the  tools,  it  is  less  expen- 
sive, and  has  not  the  unpleasant  scent  of  brick  oil,  but  unless 
carefully  prepared,  it  is  liable  to  become  thick,  and  impede  the 
action  of  the  tools. 

The  stones  to  be  engraved  are  always  previously  prepared  to 
the  general  form  by  the  lapidary,  and  frequently  they  are  set  by 
the  jeweller  before  they  are  engraved,  in  either  case  they  are  too 
short  to  be  conveniently  held  in  the  fingers,  they  are  therefore 
mounted  on  a  handle  about  five  inches  long,  and  three-quarters 
of  an  inch  diameter.  If  the  stone  has  not  been  set,  it  is  fixed 
with  lapidary's  cement  upon  a  wooden  handle,  and  to  prevent  the 
cement  from  adhering  to  the  fingers,  it  is  sometimes  coated  with 
sealing-wax.  But  if  the  stone  has  been  previously  set,  it  is 
inserted  in  a  notch  made  in  a  piece  of  cork,  or  soft  wood,  that  is 
frequently  inserted  in  the  end  of  a  piece  of  bamboo  of  appropriate 
size.  When  the  stones  are  hard,  and  have  been  previously 
polished  on  the  surfaces  that  are  to  be  engraved,  the  latter  are 
roughened,  by  rubbing  them  upon  a  soft  steel  plate  charged  with 
a  little  diamond  powder  and  oil ;  an  ordinary  plane  iron  when 
annealed  is  often  used  as  the  plate.  Sometimes  the  polish  is 
removed  from  soft  stones  by  rubbing  them  upon  a  leaden  plate 
charged  with  emery,  but  the  steel  plate  and  diamond  powder  is 
more  generally  used,  as  it  serves  equally  well  for  hard  or  soft 
stones. 

The  roughened  surface  of  the  stone  is  required  partly  because 
the  tools  penetrate  more  readily  into  the  rough  surface,  and  are 
less  liable  to  slip,  but  principally  to  enable  the  outline  of  the 
device  to  be  sketched  upon  the  stone  with  a  brass  point,  which 
is  abraded  by  the  rough  surface,  and  leaves  a  distinct  line.  In 
drawing  the  design  upon  the  stone,  the  general  outline  alone  is 
first  carefully  sketched,  the  entire  surface  enclosed  within  the 
outline  is  then  sunk,  and  the  details  of  the  design  are  afterwards 
sketched  and  sunk  in  succession. 

For  example,  in  engraving  a  shield  with  quarterings  upon  a 


ENGRAVING    SHIELD    WITH    QUARTERINGS.  1356 

seal.     The  outline  of  the  shield  is  first  drawn  with  the  brass 
point,  this  is  then  dotted  round  with  a  small  tool,  such  as  fig. 

1199,  having  a  thin  edge,  and  called  a  sharp  or  knife  tool.     The 
dots,  which  are  about  the  thirtieth  of  an  inch  long,  and  about  half 
that  distance  asunder,  serve  to  secure  the  outline,  and  prepare 
a  path  for  a  thicker  tool  with  a  rounded  edge,  such  as  fig.  1201, 
with  which  the  outline  is  perfected.     The  bulk  of  the  material, 
within  the  outline,  is  then  removed  with  a  thicker  and  larger 
tool;  having  a  rounded  edge   like   fig.   1203,  the  larger  tool 
operates  more  rapidly,  and  is  also  less  liable  to  leave  the  surfaces 
irregular,  and  therefore  as  large  a  tool  is  employed  as  can  be 
conveniently  applied  to  the  purpose.     When  the  body  of  the 
shield  has  been  sufficiently  lowered,  the  surface  is  smoothed  with 
a  smaller  and  flatter  tool,  like  fig.  1202,  which  cuts  smoother, 
and  also  allows  of  being  applied  closer  into  the  angles.     The  fine 
lines  for  the  quarterings  are  next  sketched,   and  cut  with  the 
sharp  tool,  and   the  figures  or  bearings  on  the  quarterings  are 
afterwards  sketched,  and  sunk  in  succession.     If,  as  frequently 
happens,  two  of  the  quarterings  are  similar  in  design,  they  are 
sketched   and   cut   together,    in  order   to   avoid  the   frequent 
change  of  tools,  and  also  to  ensure  greater  similarity ;  the  same 
tools  being  used  for  corresponding  parts  of  the  design.     The 
bolder  portions  of  the  bearings  are  of  course  cut  first,  and  the 
smallest  details  are  left  to  the  last.    Should  the  escutcheon  have 
a  shield  of  pretence,  this  would   be  sunk  after  the  quartering 
lines  had  been  cut,  and  if  supporters  and  garniture  were  required, 
the  entire  outline  would  be  first  sketched,  and  the  whole  advanced 
equally,  so  as  to  keep  the  general  effect  uniform. 

The  cutting  of  the  fine  parallel  lines  on  the  field,  called  colour 
lines,  presents  considerable  difficulty,  as  they  are  very  shallow, 
and  to  give  them  a  uniform  appearance  requires  much  care,  and 
a  light  but  steady  hand.  To  assist  in  cutting  these  lines  equi- 
distant, a  tool  is  used,  having  two  knife  edges,  as  shown  in  fig. 

1200,  and  called  a  colouring  tool.     The  front  edge  of  this  tool 
is  used  to  cut  the  first  line  to  the  required  depth,  and  the  second 
line  is  at  the  same  time  marked  out  by  the  back  edge ;  at  the 
next  process  the  second  line  is  cut  to  the  full  depth,  while  the 
third  line  is  marked  in  the  same  manner  and  so  on ;  the  lines 
being  cut  in  succession  from  right  to  left,   in  order  that  the 
operator  may  be  enabled  to  watch  the   progress  of  the  tool 


1357 


SEAL    ENGRAVING — COLOUR    LINES SUCCESSION 


throughout,  and  the  stone  is  held  in  an  inclined  position,  to 
cause  the  greater  penetration  of  the  front  edge  of  the  tool. 

The  colour  lines  are  sometimes  cut  before  the  bearings  are 
sunk,  but  at  other  times  they  are  left  until  nearly  all  the  other 
details  have  been  completed,  the  latter  course  is  adopted  in 
order  to  avoid  the  risk  of  injuring  the  colour  lines  should  the 
stone  happen  to  slip  in  cutting  the  bearings,  but  the  difficulty  of 
cutting  the  lines,  straight  and  equi-distant,  is  increased,  owing 
to  the  want  of  continuity  in  the  surface,  and  the  tool  is  liable  to 
cut  deeper  at  the  edges  of  the  sunken  portions.  On  this  account 
in  the  best  works  the  colour  lines  are  usually  cut  before  the 
bearings,  but  greatly  increased  care  is  then  required  in  cutting 
the  bearings. 

When  the  engraving  is  quite  finished,  the  flat  surface  of  the 
stone  is  finally  repolished  with  rottenstone  and  water,  applied 
on  a  pewter  lap,  exactly  after  the  manner  described  in  the 
chapter  on  lapidary  work. 

During  the  entire  process,  the  seal  engraver  watches  the  pro- 
gress of  the  work  through  a  lens  of  from  1  to  2  inches  focus, 
which  is  mounted  upon  an  adjustable  stand,  like  that  used  by 
watchmakers,  and  placed  immediately  over  the  tool,  and  the 
work  is  occasionally  brushed  to  allow  of  its  inspection ;  but  the 
seal  engraver  depends  also  very  much  upon  the  sense  of  feeling 
for  estimating  the  position  of  the  work,  and  upon  hearing  for 
judging  of  the  progress  of  the  tool.  To  enable  him  to  ascertain 
the  depth  and  general  effect  of  the  engraving,  he  occasionally 
takes  impressions  in  a  black  wax,  made  of  bees^-wax  and  fine 
charcoal  dust,  the  latter  is  sifted  through  muslin  and  well  worked 
into  the  wax  with  the  fingers ;  but  the  wax  is  liable  to  adhere 
to  the  fingers,  and  a  more  cleanly  method  is  to  employ  a  small 
piece  of  blue  modelling  clay. 

For  roughing  out  the  work  with  large  tools,  as  in  sinking  the 
body  of  a  large  shield,  the  engine  is  driven  rapidly,  and  the  stone 
is  applied  with  moderate  pressure  ;  in  applying  the  smaller  tools 
the  speed  employed  is  slower,  and  the  pressure  is  less ;  and  for 
the  smallest  tools  used  in  cutting  the  details,  the  pressure  is  very 
slight,  and  the  engine  is  driven  still  slower.  For  greater  steadi- 
ness in  finishing,  the  seal  engraver  sometimes  puts  the  foot  whet 
in  rapid  revolution,  and  then,  removing  his  foot  from  the  treadle 
stands  firmly  on  both  feet  while  he  applies  the  work,  until 


OF    THE    TOOLS POSITION    OF    THE    HANDS.  1  358 

tool  comes  nearly  to  rest ;  the  foot  wheel  is  then  started  again, 
and  so  on. 

From  the  circular  forms  of  the  tools,  curved  lines  and  rounded 
forms,  such  as  are  met  with  in  animals,  ornaments,  and  drapery, 
are  more  easily  executed  than  designs  composed  of  straight  lines, 
which  are  cut  most  readily  with  tools  of  as  large  a  diameter  as 
can  fairly  be  applied,  but  large  tools  cannot  be  employed  for 
cutting  the  corners  deeply,  and  therefore  small  tools  must  be  used 
for  finishing  the  corners.  To  give  definition  to  the  engraving, 
the  edges  should  be  left  nearly  vertical,  the  amount  of  bevil 
required  for  the  relief  of  the  impression,  even  in  deep  works, 
being  scarcely  perceptible.  Fine  lines  having  sharp  curves,  such 
as  the  hair  strokes  in  writing,  are  very  difficult  to  engrave ;  they 
require  very  small  knife-edged  tools,  and  the  stone  must  be 
applied  with  great  steadiness  and  delicacy ;  the  bolder  lines  in 
German  text  initials  are  much  more  easily  managed. 

In  applying  the  work  to  the  revolving  tool,  the  stone  mounted 
on  the  stick  is  supported  and  guided  in  both  hands,  the  stick 
being  held  almost  vertically  below  the  tool,  with  the  face  of  the 
stone  upwards,  so  that  both  the  tool  and  work  are  constantly 
under  observation.  The  stone  requires  to  be  held  with  great 
firmness,  but  yet  to  be  applied  with  exquisite  delicacy,  especially 
in  cutting  the  minute  details,  and  considerable  practice  is  re- 
quired to  overcome  the  difficulties  of  presenting  the  stone  to  the 
tool  with  both  decision  and  freedom. 

To  give  steadiness  to  the  arms  of  the  artist,  they  are  supported 
upon  the  bench,  but  the  position  depends  partly  upon  the  form 
of  engine  employed,  and  partly  upon  the  habit  of  the  individual. 
When  the  form  of  engine  represented  in  fig.  1196  is  employed, 
the  palm  of  the  left  hand  is  generally  rested  upon  the  hemi- 
spherical cap  of  the  engine,  while  the  forefinger  and  thumb 
embrace  the  revolving  tool,  and  grasp  the  upper  end  of  the  stick 
on  which  the  stone  is  mounted.  The  thumb  and  forefinger  of 
the  right  hand  grasp  the  stick  just  below  those  of  the  left,  and 
the  right  elbow  is  supported  upon  a  cushion  about  6  inches 
diameter;  this  position  gives  considerable  steadiness  to  the 
hands,  and  allows  of  a  free  motion  in  the  fingers,  between  which 
the  stick  is,  as  it  were,  suspended  ;  it  is,  however,  rather  adapted 
to  small  than  large  stones. 

When  the  engine  is  made  more  in  the  form  of  a  lathe  head, 


135.9  SEAL    ENGRAVING — POSITION    OP    THE    HANDS. 

and  overhangs  the  pillar,  a  different  position  of  the  left  hand  is 
generally  adopted.  In  this  case  the  left  elbow  is  supported  upon 
a  cushion,  in  the  same  manner  as  the  right,  the  two  elbows  being 
widely  separated,  to  lower  the  hands  beneath  the  tool,  and  give 
a  wide  base  to  the  arms.  The  left  hand  is  rested  against  the 
under  side  of  the  overhanging  frame,  and  in  some  cases  the  right 
wrist  is  supported  upon  a  wooden  rest,  about  6  inches  high  and 
2  inches  diameter,  having  a  hemispherical  top  to  allow  of  the 
free  motion  of  the  wrist  in  all  directions ;  and  the  base  of  the  rest 
is  enlarged  to  about  4  inches  diameter,  for  greater  steadiness. 
The  choice  of  position  is  not  very  material,  and  depends  prin- 
cipally upon  habit ;  but  those  artists  who  are  accustomed  to  one 
position  cannot  conveniently  adopt  another.  The  point  of 
greatest  importance  is,  that  both  hands  should  be  perfectly 
steady,  and  capable  of  being  moved  in  all  directions  with  great 
freedom.  The  wooden  rest  gives  great  steadiness  to  the  right 
wrist,  but  is  liable  to  interfere  with  the  free  motion  of  the  hand, 
it  is,  therefore,  often  dispensed  with,  except  for  very  delicate 
works. 

The  general  position  of  the  stick  is  nearly  vertical,  so  as  to 
keep  the  surface  of  the  stone  inclined  just  sufficiently  to  prevent 
the  stem  of  the  tool  coming  in  contact  with  the  face  of  the  stone. 
In  dotting  the  outline,  or  cutting  shallow  works  with  large  tools, 
the  stone  may  be  held  quite  horizontal ;  but  in  cutting  deep  and 
delicate  works,  or  sharp  angles,  very  small  tools  must  necessarily 
be  employed,  and  the  stone  then  requires  to  be  considerably 
inclined,  in  order  to  allow  the  edge  of  the  tool  to  penetrate  to 
the  bottom  of  the  cavity,  without  risk  of  the  stem  being  brought 
in  contact  with  the  surface  of  the  work. 

In  all  cases  in  which  the  stone  can  be  kept  horizontal,  the 
process  of  gem  engraving  is  comparatively  easy,  and  the  principal 
difficulties  that  are  met  with,  occur  in  cutting  the  curved  out- 
lines, and  in  making  a  sunk  surface  quite  flat.  As  previously 
mentioned,  the  edges  of  sunk  surfaces  should  be  made  nearly 
perpendicular,  to  give  definition  to  the  impression,  and  the  out- 
linos  are  cut  with  a  thin  tool  like  fig.  1201,  in  which  the  face  of 
the  tool  is  flat,  but,  to  give  strength,  the  back  is  necessarily  mad< 
conical. 

In  those  cases  in  which  the  flat  face  of  the  tool  can  be  appli( 
to  the  convex  side  of  a  curved  recess,  no  material  difficulty  i* 


CUTTING    CURVED    LINES SINKING    FLAT    SURFACES.  1360 

experienced  in  cutting  the  outline  nearly  perpendicular,  as  the 
stone  can  be  slowly,  but  continuously,  twisted  round,  to  bring 
every  successive  part  of  the  curve  in  a  direct  line  with  the  flat 
face  of  the  tool,  and  should  the  edge  of  the  outline  be  irregularly 
cut  at  the  first  attempt,  a  second  cut  may  be  taken  with  a  smaller 
tool  in  the  same  manner,  to  correct  the  irregularities  of  the 
edge,  and  during  the  entire  process  the  tool  and  work  remain 
constantly  under  observation. 

But  it  will  be  readily  conceived  that  the  flat  face  of  the  tool 
cannot  be  so  conveniently  applied  to  the  concave  side  of  the 
recess,  as  the  edges  would  have  a  continual  tendency  to  encroach 
upon  the  curved  line,  and  therefore,  in  cutting  around  the  con- 
cave side  of  a  curve,  the  conical  back  of  the  tool  must  be  made 
to  traverse  around  the  inside  of  the  curve,  but  the  back  of  the 
tool  being  less  under  observation  than  the  face,  it  is  much  more 
difficult  to  cut  the  edge  smoothly,  and  in  any  attempts  to  correct 
the  irregularities  with  a  smaller  tool,  it  is  necessary  to  adopt  the 
same  course  of  applying  the  back  of  the  tool  to  the  concave  edge 
of  the  work,  as  it  is  found  that  when  the  edge  has  been  cut  with 
the  back  of  the  tool,  the  face  cannot  be  successfully  applied  to 
rectify  any  minute  errors. 

The  difficulty  of  making  a  sunken  surface  quite  flat,  arises 
from  the  circumstance  that  the  entire  face  has  to  be  produced 
with  only  a  very  small  portion  of  the  edge  of  the  tool,  and  with- 
out any  mechanical  guidance  being  derived  from  the  tool  itself. 
For  although  the  edge  of  a  tool,  such  as  fig.  1202,  maybe  turned 
very  nearly  flat,  still  on  examination  after  being  used,  it  will 
always  be  found  rather  convex,  owing  to  the  circumstance  that 
the  edge  has  a  constant  tendency  to  wear  the  fastest  at  the 
margins,  and  the  rounded  edge  of  the  tool  has,  of  course,  a  con- 
tinual tendency  to  cut  the  surfaces  to  which  it  is  applied  into  a 
series  of  small  hollows,  instead  of  one  continuous  plane. 

In  flattening  a  sunken  surface,  or,  as  it  is  sometimes  called, 
stippling,  the  difficulty  is  overcome  by  keeping  the  stone  in  con- 
tinual but  steady  motion.  The  stone  being  quickly  traversed 
with  very  short  strokes  beneath  the  tool,  the  entire  surface  is 
successively  passed  under  the  lowest  point  of  the  tool,  which  is 
only  allowed  to  cut  at  the  highest  points  of  the  surface,  and 
these  are  determined  apparently  by  intuition,  so  delicate  is  the 
sense  of  feeling  acquired  by  the  best  gem  engravers ;  but,  as 


1361  GEM    ENGRAVING POSITION    OF    THE    STONE. 


may  be  imagined,  this  great  dexterity  of  hand  is  only  to  be 
acquired  by  long  and  patient  practice. 

When  the  stone  requires  to  be  much  inclined  from  the  per- 
pendicular, to  allow  small  tools  to  penetrate  into  the  minute 
details  of  deep  works,  the  difficulties  of  gem  engraving  are 
materially  increased.  As  previously  mentioned,  some  of  the 
little  disks  are  less  than  one  hundreth  of  an  inch  in  diameter, 
while,  to  afford  sufficient  stiffness  to  the  tool,  the  diameter  of  the 
stem  requires  to  be  about  one  eighth  of  an  inch  at  the  back,  and 
the  front  end  is  made  conical  for  about  1  inch  of  its  length  from 
the  disk,  as  seen  in  the  greatly  enlarged  section,  fig.  1207.  To 
enable  these  small  tools  to  penetrate  even  into  a  flat  surface,  it 
is  obvious  that  the  stone  must  be  inclined  to  a  greater  angle  than 
the  cone  of  the  stem,  or  the  latter  would  rub  on  the  flat  surface; 
but  in  finishing  a  deep  corner,  so  as  to  make  it  quite  square  and 
sharp  at  the  bottom,  the  stone  must  be  inclined  to  a  much 
greater  angle,  and  in  consequence,  instead  of  the  tool  cutting 
perpendicularly  downwards,  it  cuts  obliquely,  at  the  same  angle 
as  that  at  which  the  stick  is  held,  and  this  tendency  of  the  tool 
requires  to  be  overcome  by  the  tact  of  the  artist. 

In  the  case  of  squaring  a  corner,  there  is  generally  sufficient 
room  in  the  sunken  portion  to  allow  the  entire  disk  to  be  inserted 
within  the  cavity,  upon  the  side  of  which  it  is  principally  required 
to  operate,  and  the  surface  of  the  stone  may  be  held  nearly 
vertical.  But  in  cutting  fine  lines  on  a  deep  surface,  such  as 
some  of  the  finishing  lines  in  the  hair  of  a  deeply  sunk  head,  the 
lines  do  not  admit  of  being  made  much  wider  than  the  edge  of 
the  tool.  Very  delicate  management  is  required  to  sink  these 
lines  perpendicular  to  the  general  surface,  and  the  stone  must 
be  applied  to  the  tool  so  as  to  commence  the  line  a  little  above 
the  exact  position  for  the  center  of  the  line,  in  order  that  the 
oblique  cut,  when  made  to  the  appropriate  depth,  may  terminate 
in  the  desired  position. 

In  ordinary  seal  engraving,  great  accuracy  of  finish  in  the 
details  is  never  attempted,  and  these  difficulties  of  manipulation 
are  not  severely  felt,  but  they  are  a  great  obstacle  to  the  prac- 
tice of  the  higher  department  of  gem  sculpture,  which  not  only 
requires  the  artist  to  possess  great  talent  for  the  conception  of 
beautiful  designs  in  sculpture,  but  he  must  also  devote  many 
years  to  the  attainment  of  sufficient  mechanical  dexterity,  to 


ENGLISH  GEM  ENGRAVERS — POLISHING  EXGRAVED  SURFACES.     1362 

enable  him  to  realise  in  detail  the  conceptions  of  his  mind.  The 
gem  engraver  also  labours  under  the  further  disadvantage,  that 
from  the  minute  and  delicate  character  of  his  works,  they  can 
only  be  properly  appreciated  by  those  few  persons  who  have 
carefully  studied  the  subject. 

It  is  very  generally  supposed  that  the  ancients  greatly  excelled 
the  moderns  in  gem  engraving,  and  that  the  art  has  never  been 
carried  to  the  highest  perfection  in  this  country.  Mr.  Henry 
Weigall,  however,  states  that  "  this  supposition  is  erroneous, 
and  has  probably  arisen  from  the  fact  of  travellers  supposing 
that  the  collections  of  gems  and  impressions  that  they  have  made 
in  Italy,  are  exclusively  the  works  of  Italian  artists. ;  such,  how- 
ever, is  not  the  case,  and  I  have  myself  had  the  satisfaction  of 
pointing  out  to  many  such  collectors,  that  the  most  admired 
specimens  in  their  collections  were  the  works  of  English  artists. 
Selections  may  be  made  from  the  works  of  Wray,  Burch,  Mar- 
chant,  and  Charles  Weigall,  which  will  bear  a  comparison  with 
the  finest  works  that  have  been  produced  in  any  age  or  country." 

Mr.  Henry  Weigall  could  not,  of  course,  speak  of  his  own 
performances,  but  the  reputation  his  works  have  acquired  in  this 
and  other  countries  would  fully  justify  the  insertion  of  his  name 
in  the  above  list. 

The  engraved  surfaces  of  ordinary  works,  such  as  armorial 
bearings,  are  commonly  left  from  the  cutting  tools,  and  are  not 
afterwards  polished  ;  but  in  superior  specimens  of  gem  engraving, 
when  it  is  desired  to  give  the  work  the  highest  possible  finish, 
the  engraved  surfaces  are  all  polished  in  the  most  careful  manner. 
For  this  purpose  the  surfaces  are  first  smoothed  with  copper 
tools,  made  of  the  same  shapes  as  the  finishing  tools  used  in 
engraving,  and  charged  in  the  same  manner  with  diamond 
powder  and  oil ;  but  the  diamond  powder  is  ground  finer  than 
that  used  in  engraving,  and  the  copper  tools  being  softer  than 
those  of  iron,  the  particles  of  diamond  become  more  deeply 
embedded  in  the  surface  of  the  tools,  and  therefore  leave  a  much 
smoother  surface.  After  all  the  engraved  surfaces  have  been 
smoothed  with  copper  tools,  similar  tools  made  of  boxwood, 
charged  with  still  finer  diamond  powder,  are  employed  to  com- 
plete the  smoothing.  The  boxwood  tools  cut  very  smoothly,  and 
leave  almost  a  semi-polish,  which  is  completed  with  copper  tools, 
charged  with  rottenstone  and  water. 

VOL.  III.  Z 


1363         GEM    ENGRAVING QUALITIES    OF    DIFFERENT    STONES. 

The  process  of  polishing  minute  works  with  much  detail  is, 
however,  very  tedious,  as  every  one  of  the  markings  requires  to 
be  operated  upon  separately,  and  the  process  demands  much 
skill  and  attention  to  prevent  the  sharpness  and  delicacy  of  the 
engraving  from  being  deteriorated.  To  economise  time  in 
polishing  common  works,  where  precision  of  form  in  the  details 
is  not  considered  of  primary  importance,  scratch  brushes  are 
sometimes  employed ;  these  are  made  of  fine  copper  wire  fixed 
in  the  end  of  a  tool,  and  sometimes  bent  up  at  right  angles  to 
the  axis,  to  make  a  small  wheel  brush,  which  is  charged  in  like 
manner  with  rottenstone  and  water,  but  the  practice  is  not  to 
be  recommended,  as  it  obliterates  the  delicate  forms. 

The  process  of  seal  engraving  is  applied  to  all  gems  inferior  in 
hardness  to  the  diamond,  and  even  this  is  said  to  have  been 
engraved  in  some  rare  instances.  The  sapphire  cuts  very  slowly 
but  smoothly ;  the  ruby  cuts  slowly,  but  small  pieces  are  liable 
to  break  off  in  flakes  ;  carnelian  and  bloodstone  are  close  in  their 
structure,  and  admit  of  being  cut  with  very  smooth  surfaces. 
Softer  stones  admit  of  being  cut  more  rapidly,  but  do  not  when 
finished  present  such  smooth  surfaces  as  the  harder  and  more 
compact  materials.  The  amethyst  is,  perhaps,  as  soft  a  stone  as 
can  be  cut  very  smoothly,  nevertheless,  glass  and  even  marble 
are  sometimes  successfully  treated  by  the  seal  engraver,  but  the 
tools  soon  become  deteriorated,  owing  to  the  diamond  powder 
becoming  embedded  in  these  soft  materials.  When  the  stones 
consist  of  layers  of  different  degrees  of  hardness,  increased  caution 
is  required  to  prevent  the  tool  penetrating  more  deeply  at  the 
softer  parts.  An  onyx  engraved  in  intaglio,  so  that  the  device 
is  seen  from  the  surface  in  the  colours  of  the  lower  stratum,  is 
called  a  nicolei. 


- 

The  very  excellent  proof  impressions  of  seals,  taken  in  wax  by 
the  seal  engravers,  are  produced  in  the  following  manner.  The 
stone  is  first  thoroughly  cleaned  with  a  moderately  soft  brush,  it 
is  then  warmed  over  the  flame  of  a  candle,  the  stone  being 
traversed  in  a  circle  at  a  moderate  distance  above  the  flame, 
that  it  may  be  heated  uniformly.  If  the  stone  were  held  sta- 
tionary above  the  flame  it  would  be  liable  to  be  cracked,  from 
one  portion  being  heated  more  rapidly  than  another.  The  usual 


TAKING    PROOF    IMPRESSIONS    OF    SEALS. 

test  for  the  proper  degree  of  heat,  is  the  placing  of  the  seal  upon 
the  naked  hand,  and  if  the  heat  is  about  as  great  as  can  be  borne 
by  a  tolerably  sensitive  hand  without  causing  pain,  it  is  consi- 
dered to  be  suitable.  The  engraved  surface  of  the  seal  is  then 
coated  with  a  very  thin  layer  of  clean  tallow,  applied  with  a 
small  brush,  such  as  a  rather  soft  nail  brush,  and  the  tallowed 
surface  is  again  coated  with  a  thin  layer  of  vermilion,  applied 
with  a  camel's  hair  pencil.  This  completes  the  preparation  of 
the  seal,  and  when  the  impression  is  made,  the  vermilion  becomes 
attached  to  the  surface  of  the  wax,  and  materially  heightens  the 
beauty  of  the  impression. 

The  sealing-wax  is  prepared  by  holding  the  stick  of  wax  at  a 
little  distance  above  the  flame  of  the  candle,  until  it  is  thoroughly 
softened,  but  it  is  only  so  far  heated  as  is  necessary  to  allow  of 
a  sufficient  quantity  of  wax  being  detached  to  form  the  impres- 
sion, and  care  is  taken  to  avoid  blackening  the  wax,  either  by 
smoke,  or  allowing  it  to  become  ignited.  The  softened  wax  is 
deposited  in  a  small  heap  upon  a  piece  of  stout  paper,  and  when 
enough  to  form  the  impression  has  been  placed  on  the  paper, 
the  fusion  of  the  wax  is  completed  by  traversing  the  under  sur- 
face of  the  paper  above  the  flame  of  the  candle,  at  a  sufficient 
distance  to  avoid  scorching  the  paper. 

When  the  wax  has  become  thoroughly  softened,  it  is  stirred 
with  a  small  stick,  to  drive  out  all  the  air  bubbles,  and  work  it 
into  a  uniform  mass  of  a  conical  shape  ;  the  paper  is  then  laid 
upon  the  table,  and  when  the  surface  of  the  wax  has  become 
bright  and  quiescent,  the  seal  is  applied  to  give  the  impression. 
In  order  that  both  the  seal  and  wax  may  be  at  the  requisite 
temperatures,  the  preparation  of  the  two  is  carried  on  almost 
simultaneously,  and  usually  the  seal  is  held  over  the  flame  of  the 
candle  for  a  few  seconds  to  restore  the  heat,  while  the  wax  is 
assuming  the  quiescent  state. 

In  applying  the  seal  to  the  wax,  the  seal  handle  is  held  between 
the  thumb  and  the  first  two  fingers,  applied  as  near  to  the  seal 
as  convenient.  To  give  steadiness  to  the  hand,  the  wrist  is 
rested  upon  the  surface  of  the  table,  and  the  position  having 
been  carefully  determined,  the  seal  is  quickly  dabbed  upon  the 
wax,  with  a  firm  perpendicular  stroke,  but  with  only  moderate 
force.  Some  little  practice  is  necessary  to  attain  sufficient  dex- 
;  terity  to  give  the  impression  with  precision ;  but  the  method  of 


1365 


CAMEO    CUTTING. 


quickly  dabbing  the  seal  upon  the  wax,  yields  far  more  defined 
impressions  than  the  mode  sometimes  adopted  of  applying  the 
seal  with  quiet  but  considerable  pressure,  which  not  only  fails  to 
copy  the  most  delicate  of  the  lines  and  angles,  but  the  imperfect 
copy  thus  produced  is  also  liable  to  be  further  deteriorated  by 
the  seal  sliding  on  the  gradually  yielding  wax,  which  then  receives 
a  double  impression. 

In  this,  as  in  similar  processes,  the  most  sharply  defined  impres- 
sions are  produced  by  employing  sufficient  momentum  to  drive 
the  wax  at  the  same  instant  into  all  the  minute  crevices  of  the 
seal,  exactly  as  in  the  clichee  casting  and  type  founding,  alluded 
to  at  page  324,  Vol.  i. 


SECTION  II. CAMEO    CUTTING. 

CAMEO  cutting,  or  the  engraving  of  gems  in  relief,  is  effected 
with  the  same  apparatus,  and  by  the  same  general  methods  as 
those  employed  in  engraving  corresponding  forms  in  intaglio,  and 
both  arts  are  occasionally  practised  by  the  same  individuals. 
The  principal  differences  in  the  manipulations  of  the  seal 
engraver  and  the  cameo  cutter  arise  from  the  design  being  in 
the  former  case  wrought  concave,  and  in  the  latter  convex.  The 
tools  with  which  the  former  are  produced,  being  themselves  con- 
vex, they  may  in  most  cases  be  selected  of  counterpart  curva- 
tures to  the  concave  details  required  in  intaglio  engraving ;  but  [ 
the  convex  forms  in  cameo  cutting,  have  to  be  produced  with 
convex  tools,  which  cannot  therefore  be  selected  of  counterpart 
forms,  but  the  convex  surfaces  have  to  be  produced  by  twisting 
the  stone  about  at  all  angles  beneath  the  rounded  edge  of  the 
tool.  For  this  reason  the  engraving  of  gems  in  relief,  is  usually 
considered  to  be  more  difficult  than  engraving  in  intaglio.  On 
the  other  hand,  however,  the  deep  recesses  in  cameos  are  gene- 
rally more  accessible  than  those  in  intaglio,  and  the  principal 
source  of  difficulty  in  gem  engraving  is  therefore  in  some 
measure  avoided. 

The  stones  selected  for  engraving  in  cameo,  are  generally  those 
called  onyxes  consisting  of  two  layers  of  different  colours  forming 
a  strong  contrast,  as  the  black  and  white  layers  of  the  agate,  or 
the  red  and  white  layers  of  the  carnelian.  The  design  is  almost 
always  engraved  exclusively  in  the  white  layer,  and  the  dark 


ONYX,    APPLICATION    OF    THE    TERM.  1366 

coloured  layer  forms  the  back  ground,  the  contrast  of  the  two 
colours  serving  to  render  the  design  more  distinct.  Sometimes 
onyx  stones  having  three  or  more  layers  of  colours  are  employed 
for  cameos,  these  are  selected  when  either  from  the  great  amount 
of  relief  desired  in  the  engraving,  the  thickness  of  the  white 
layer  would  be  insufficient  to  allow  of  the  entire  design  being 
engraved  in  it,  or  that  it  is  desired  to  make  the  most  prominent 
parts  of  the  design  of  different  colours  in  order  to  improve  the 
effect. 

Mineralogists  generally  restrict  the  name  onyx  to  a  variety  of 
chalcedony,  consisting  of  alternate  layers  of  brown  and  opake 
white,  but  those  artists  who  work  in  precious  stones  usually 
attach  a  much  more  extended  signification  to  the  name,  and  the 
following  interesting  particulars  from  the  pen  of  Mr.  H.  Weigall 
will  explain  the  cause  of  these  discrepancies. 

"All  the  stones  in  different  coloured  layers  employed  for 
cameos,  are  known  to  practical  men  by  the  general  name  of 
onyxes;  but  some  confusion  has  arisen  with  regard  to  the 
nomenclature  of  stones  of  this  class,  in  consequence  of  the 
imperfect  information  of  those  authors  who  have  undertaken  to 
describe  them.  It  is  a  remarkable  fact  that  no  author  who  has 
undertaken  to  describe  the  onyx,  has  given  this  simple,  and  to 
all  practical  persons,  intelligible,  description  of  it,  namely,  a 
stratified  stone  occurring  in  any  of  the  semi-transparent  or 
opaque  varieties ;  thus  there  is  the  onyx  of  the  sard,  called  the 
sardonyx,  that  of  the  carnelian  called  the  carnelian  onyx,  and  so 
on  through  the  whole  variety  of  stones. 

"  The  name  onyx  is  derived  from  a  Greek  word  which  signi- 
fies nail,  and  the  authors  before  referred  to,  have  evidently  been 
perplexed  to  make  out  any  resemblance  between  such  an  object, 
and  that  particular  variety  of  the  onyx  which  they  happened  to 
describe.  Thus  Pliny  could  see  no  resemblance  to  a  human  nail 
in  the  specimen  from  which  he  took  his  description  of  the  onyx 
(which  appears  to  have  been  a  bad  sardonyx),  and  he  therefore 
thought  it  must  be  a  horn  or  hoof,  and  fancied  a  resemblance  to 
a  horse's  hoof.  Theophrastus  seems  to  have  described  a  cloudy 
specimen  of  the  carnelian  as  the  onyx,  and  he  fancies  it  resem- 
|bles  the  pink  and  white  colours  sometimes  observable  on  the 
I  human  nail." 

Mr.  H.  Weigall  however  suggests  that  there  was  an  original 


1367  CAMEO-CUTTING ADAPTATION    OF    THE    DESIGN    TO 


! 


propriety  in  the  name,  and  that  it  most  probably  arose  from  the 
practice  of  the  ancients  in  staining  their  nails,  for  if  the  stain 
were  only  applied  at  distant  intervals  of  time,  the  lower  portion 
of  the  nail  would  grow  between  the  applications,  and  present  a 
band  of  white  at  the  bottom  of  the  coloured  nail,  and  thus  render 
it  a  fair  type  of  the  onyx  stone. 

Mr.  Weigall  has  made  inquiries  of  travellers  who  have  visited 
those  Eastern  nations  where  the  practice  of  staining  the  nails  is 
still  continued,  and  has  found  this  view  to  be  corroborated,  as 
they  agree  in  stating  that  the  nails  commonly  present  two  colours 
exactly  resembling  an  onyx. 


The  stones  to  be  cut  into  cameos  are  prepared  by  the  lapidary, 
and  to  avoid  wasting  the  material,  each  stone  is  left  as  large  as 
possible.  The  cameo  cutter  has  therefore  to  select  a  stone  as 
nearly  as  he  can  in  accordance  with  his  intended  design,  which 
must  be  afterwards  modified  in  some  degree  to  suit  the  stone. 

As  a  preliminary  step  to  cutting  the  cameo,  it  is  most  impor- 
tant that  the  artist  should  have  a  clear  conception  both  of  the 
design,  and  the  capabilities  of  the  stone.  To  assist  in  this,  he 
first  makes  a  sketch  of  the  design  on  an  enlarged  scale,  and  then 
having  considered  the  degree  of  relief,  that  will  be  adapted  to 
the  thickness  of  the  white  layer,  he  makes  a  model  in  wax  of  the 
exact  size  of  the  stone. 

With  unimportant  works  this  is  frequently  omitted  by  prac- 
tised artists,  who  depend  upon  their  skill  for  overcoming  any 
difficulties  that  may  arise,  but  it  is  at  all  times  a  great  assistance 
in  elaborate  works,  especially  to  those  who  have  not  great  prac- 
tice. The  model  and  stone  are  carefully  compared,  and  any 
alterations  that  may  be  demanded  by  the  formation  of  the  stone, 
are  first  made  in  the  model. 

When  the  stone  is  in  three  layers,  additional  care  is  required 
to  adapt  the  design  to  the  stone.  It  is  at  all  times  desirable 
that  the  line  of  division  between  the  colours  of  the  two  layers 
forming  the  ground  and  figure  should  be  distinctly  defined,  but 
it  is  sometimes  an  advantage  when  the  transition  between  the 
two  colours  in  the  upper  layers  is  more  gradual.  For  instance, 
in  cutting  the  head  of  a  Medusa,  in  a  carnelian  having  one  layer 
of  white  between  two  of  red,  if  the  lines  of  division  between 


THE    STONE SPADE SHELL    CAMEOS.  1368 

both  the  layers  of  red  and  the  white  were  sharply  defined, 
the  features  must  be  cut  entirely  out  of  the  white  layer,  and  the 
upper  layer  of  red  must  be  reserved  for  the  snakes,  but  if  the 
transition  between  the  upper  layer  of  red  and  the  white  were 
gradual,  a  faint  tinge  of  colour  might  be  left  on  the  cheek  with 
great  advantage  to  the  effect,  and  the  skilful  engraver  of  cameos 
will  thus  avail  himself  of  every  opportunity  for  heightening  the 
'ect  that  is  offered  by  the  formation  of  the  stone.  When  the 
tone  consists  of  several  layers  of  colour,  considerable  scope  is 
afforded  for  the  exercise  of  the  judgment,  in  selecting  a  design 
in  which  the  whole  of  the  colours  can  be  rendered  available. 

When  the  design  has  been  accommodated  to  the  stone  as 
nearly  as  possible,  the  outline  is  sketched  on  the  surface,  and 
cut  in  with  a  knife-edged  tool,  and  the  superabundant  portions 
of  the  white  layer  beyond  the  outline  are  removed  down  to  the 
dark  layer  forming  the  ground.  The  general  contour  of  the 
figure  is  next  formed,  and  this  is  followed  by  the  principal  details, 
which  are  sketched  and  cut  in  succession,  care  being  taken  to 
preserve  sufficient  material  at  the  most  prominent  parts,  and  to 
advance  the  engraving  uniformly,  so  that  the  general  effect  may 
be  compared,  from  time  to  time,  with  that  of  the  wax  model. 

The  surface  of  the  back  ground  is  conveniently  flattened  with 
the  broad  flat  surface  of  a  tool  such  as  fig.  1201,  and  the  diffi- 
ulty  of  removing  the  little  irregularities  on  the  rounded  surfaces 
f  the  figure,  with  the  convex  edge  of  a  revolving  tool,  may  be 
tirely  avoided  by  the  use  of  a  tool  called  a  spade,  consisting  of 
piece  of  soft  iron  about  3  or  4  inches  long,  the  end  of 
hich  is  filed  at  an  angle  of  45  degrees,  and  charged  with 
iamond  powder.  The  spade  is  held  in  the  fingers  like  a  pencil, 
d  rubbed  with  short  strokes,  either  straight  or  circular,  to 
uce  the  irregularities  of  the  surface.  The  last  delicate  touches 
e  executed  with  very  small  tools,  and  the  cameo  is  finally 
oothed  and  polished  in  the  same  manner  as  the  best  works  in 
taglio. 

The  method  of  carving  cameos  in  conch  shell,  described  on 
1094  to  1097  of  this  volume,  is  more  expeditious,  and 
resents  much  less  difficulty,  than  the  engraving  of  cameos  on 
gems,  but  the  shell  cameos  do  not  admit  of  the  delicate  cutting 
and  elaborate  finish  usually  bestowed  on  true  cameos,  and  they 
are  also  much  less  durable. 


1869  GLASS  ENGRAVER'S  TOOLS. 


SECTION    III. GLASS    ENGRAVING. 

ENGRAVING  on  glass  is  executed  in  much  the  same  manner  as 
seal  engraving,  and  with  tools  of  similar  forms,  but  the  designs 
on  glass  works  are  usually  of  larger  sizes  than  those  on  gems, 
and  the  tools  are  therefore  made  of  proportionately  greater 
diameter.  In  order  to  permit  large  objects,  such  as  decanters 
or  squares  of  glass,  to  be  applied  to  the  wheels,  the  latter  are 
fixed  on  stems  that  project  from  six  to  ten  inches  from  the  front 
of  the  lathe  head,  or  as  it  is  generally  called,  the  tool. 

The  wheels  employed  for  engraving  are  made  of  copper,  and 
charged  with  fine  flour  emery  and  oil.  When  the  engraved 
surfaces  are  required  to  be  polished,  similar  wheels  made  of  lead, 
charged  with  pumice  stone  powder  and  water,  are  used. 

The  glass  engraver's  tool  shown  in  fig.  1208,  like  the  engine 
used  by  the  seal  engraver,  is  mounted  upon  a  stout  bench  about 
2  feet  6  inches  high,  and  driven  by  a  treadle  and  foot  wheel, 
from  18  to  24  inches  diameter.  The  metal  frame  that 
carries  the  mandrel  is  supported  upon  a  wooden  pillar,  called 
the  stock)  which  is  generally  of  such  a  height  as  to  place  the 
center  of  the  mandrel  about  10  inches  above  the  surface  of  the 
bench,  in  order  to  allow  sufficient  room  for  applying  the  objects 
to  be  engraved  to  the  lower  edges  of  the  wheels. 

For  works  of  ordinary  sizes,  the  mandrel  is  made  about  8 
inches  long,  and  is  supported  at  the  left  hand  end  in  bearings, 
about  4  inches  asunder.  The  remaining  portion  of  the  man- 
drel projects  from  the  front  of  the  tool,  for  the  purpose  of 
receiving  and  supporting  the  spindles  of  the  wheels,  which  are 
made,  as  shown  in  fig.  1209,  with  a  conical  plug  cast  on  a  cen- 
tral wire  about  10  inches  long,  and  the  copper  wheels  which 
vary  in  size,  from  about  one-eighth  of  an  inch  to  4  inches 
diameter,  are  screwed  or  ri vetted  on  the  ends  of  the  wires. 

The  overhanging  portion  of  the  mandrel  has  a  conical  hole, 
measuring  about  half  an  inch  diameter,  at  the  larger  end,  and 
one  quarter  of  an  inch  at  the  smaller  end,  for  the  reception  of 
the  leaden  plug  on  the  spindle  of  the  wheel,  which  is  cast  either 
in  the  cavity  of  the  mandrel  itself,  or  in  a  mould  of  correspom 
ing  form,  made  like  that  of  the  seal  engraver,  shown  in  fig.  119< 


GLASS  ENGRAVER'S  TOOLS. 


1370 


and  having  in  like  manner  a  nick  in  one  side,  to  form  a  feather, 
that  fits  into  a  similar  nick  in  the  mandrel. 

In  the  tool  shown  in  fig.  1208,  a  small  cylindrical  hole  extends 
from  the  bottom  of  the  conical  hole  to  the  back  end  of  the  man- 
drel, to  allow  of  the  passage  of  the  spindle,  which  projects 
slightly  beyond  the  end  of  the  mandrel,  in  order  that  the  plug 
may  be  loosened,  by  gently  tapping  the  end  of  the  spindle. 
More  generally,  however,  the  spindle  does  not  extend  throughout 
the  length  of  the  mandrel,  but  a  transverse  mortise  is  made 


FIGS. 
1208. 


1209. 


1210. 


1211. 


through  the  mandrel,  just  behind  the  front  bearing,  and  the 
spindle  is  only  made  of  sufficient  length  to  extend  partly  across 
the  mortise,  in  this  case  the  spindle  is  released  by  inserting  a  lever 
or  wedge. 

Several  other  unimportant  variations  are  occasionally  made  in 
the  construction  of  the  apparatus,  which  is  sometimes  made  of  a 
much  larger  size,  in  order  to  carry  wheels  of  8  or  10  inches 
diameter,  but  these  large  wheels  are  principally  required  for 
common  works,  such  as  glass  shades,  and  the  process  then  more 
nearly  resembles  glass  cutting. 

The  edges  of  the  wheels  employed  in  glass  engraving,  like 
those  used  by  the  seal  engraver,  are  made  in  a  great  variety  of 
forms,  but  mostly  square,  angular,  or  rounded,  and  the  thick- 


1371  GLASS  ENGRAVER'S  WHEELS. 


nesses  of  the  wheels  vary  from  about  one  quarter  of  an  inch  to  a 
knife  edge ;  but  from  the  large  diameter  of  the  wheels  mostly 
used,  and  the  comparative  shallowness  of  the  engraving,  it  is  not 
generally  necessary  to  incline  the  surface  to  be  engraved,  in 
order  to  avoid  the  spindles  ;  and  therefore  the  edges  of  the 
wheels  used  for  flat  surfaces  are  made  cylindrical,  as  shown  in 
fig.  1209,  instead  of  being  conical  as  in  the  corresponding  tool 
for  seal  engraving,  seen  in  fig.  1202. 

For  very  minute  works  in  glass  engraving,  however,  such  as 
are  met  with  in  small  figures  of  animals,  architectural  views,  or 
landscapes,  wheels  not  exceeding  about  the  fiftieth  of  an  inch  in 
diameter  are  required.  The  edges  of  these  small  wheels  are 
formed  exactly  like  the  tools  of  the  seal  engraver,  and  in  like 
manner  are  made  of  carefully  annealed  iron  wire,  first  roughly 
filed  into  form,  and  then  carefully  turned  down  to  the  required 
sizes  with  the  graver.  But,  as  previously  intimated,  glass  is  too 
soft  a  material  to  be  smoothly  engraved  with  iron  wheels ;  iron 
is  therefore  only  employed  for  those  wheels  that  are  too  small 
to  be  made  as  copper  disks  attached  to  iron  stems. 

In  charging  the  wheels  for  engraving,  fine  washed  flour  emery 
is  mixed  with  olive  oil,  in  a  small  shallow  saucer,  which  is  fre- 
quently applied  to  the  lower  edges  of  the  revolving  tool.  The 
lead  wheels  for  polishing  are  charged  in  a  similar  manner,  with 
pumice  stone  powder  mixed  with  water. 

To  prevent  the  wet  powders  from  being  thrown  against  the 
person  of  the  artist  by  the  centrifugal  force,  a  light  radial  arm 
is  attached  by  a  screw  to  a  cap  mounted  on  the  mandrel  frame, 
as  seen  at  a.  The  arm  is  made  of  sufficient  length  to  extend  a 
little  beyond  the  edge  of  the  wheel,  and  has  near  the  end  a  long 
slit,  cut  at  a  few  degrees  from  the  perpendicular,  through  which 
is  passed  a  thin  strip  of  metal,  or  wood,  about  one  inch  wide, 
and  tapered  at  its  lower  end,  which  is  adjusted  for  height,  so  as 
to  rest  against  the  upper  edge  of  the  wheel. 

Glass  engraving  is  principally  applied  to  the  smooth  surfaces 
left  by  the  glass  blower,  but  sometimes  for  greater  elaboration, 
the  works  are  prepared  by  the  glass  cutter,  and  whether  the 
general  surface  be  greyed,  or  polished,  the  engraving  is  not  com- 
menced until  the  object,  such  as  a  decanter  or  wine  glass,  is 
completed  in  all  other  respects.  The  glass  engraver  first  sketches 
the  general  outline  of  the  design  with  a  pen  and  ink,  or  more 


- 


GLASS    ENGRAVING.  1372 

generally  some  fine  powder,  such  as  powdered  chalk,  mixed  with 
a  little  gum  water.  The  engravings  on  glass  being  mostly 
shallow,  do  not  require  to  have  the  outlines  deeply  cut,  as  in 
seal  engraving,  but  the  broad  surfaces  are  at  once  produced, 
with  large  tools  having  flat,  or  rounded  edges,  which  are  applied 
first  to  the  center  of  the  surface,  and  this  is  gradually  enlarged 
until  it  reaches  the  outline.  The  secondary  parts  of  the  design 
are  then  sketched,  and  cut  in  like  manner  with  smaller  tools, 
and  as  the  minute  details  are  approached,  smaller  and  thinner 
Is  are  employed,  just  as  in  seal  engraving. 
When  the  designs  are  simple,  and  do  not  require  great  exact- 
ness, the  general  outline  alone  is  sketched,  and  even  this  is  in 
some  cases  omitted,  when  the  same  design  has  been  frequently 
repeated,  but  where  great  precision  is  required,  all  the  details 

sketched  and  cut  in  succession. 

In  applying  the  object  to  the  wheels,  it  is  grasped  in  both 
ds,  and  held  against  the  lower  edge  of  the  tools,  moderate 
iure  is  required  to  cause  the  larger  tools  to  penetrate,  but  the 
all  tools  require  very  little  pressure.  The  arms  are  steadied 
by  resting  each  elbow  upon  a  leather  cushion,  but  the  large  sizes 
of  the  works  do  not  allow  of  the  hand  being  rested  against  the 
lathe  as  in  seal  engraving.  The  designs  are  also  larger,  and 
require  greater  freedom  of  motion  in  the  hands,  the  weight  of 
large  articles,  such  as  decanters,  also  increases  the  difficulty, 
he  execution  of  small  and  highly  finished  designs,  therefore, 
quires  great  delicacy  of  touch,  and  much  practice,  but  not- 
ithstanding  these  difficulties,  very  beautiful  specimens  of  the 
t  are  sometimes  produced. 

When  the  general  surface  of  the  object  is  polished,  the 
graving  is  mostly  left  grey  from  the  emery  tools,  but  when  the 
neral  surface  is  greyed,  the  surfaces  of  the  engraving  are 
lished,  in  order  that  it  may  show  by  contrast ;  sometimes, 
wever,  the  effect  is  heightened  by  combining  the  two  methods, 
metimes  very  pretty  effects  are  produced  by  employing  glass 
two  colours,  in  this  case  the  body  of  the  article  is  made  in 
colourless  flint  glass,  which  is  afterwards  covered  with  a  thin 
coat  of  coloured  glass,  and  the  design  is  developed  by  cutting 
entirely  through  the  coloured  coat  so  as  to  leave  the  pattern 
colourless.  At  other  times  the  coloured  glass  is  left  to  form  the 
design,  and  the  portions  around  are  removed  to  show  a  colour- 


1373 


GLASS    EN7GRAVING. 


less  panel.  In  more  elaborate  works,  the  design  is  sometimes 
formed  entirely  in  the  coloured  glass,  which  in  this  case  is  left 
thicker,  and  the  effects  of  light  and  shade  are  produced  by  cutting 
nearly  through  the  coloured  coat  for  the  highest  lights,  and  leav- 
ing the  deepest  shades  of  the  full  thickness  of  the  coloured  coat. 
When  well  executed  and  placed  between  the  eye  and  the  light, 
these  works  present  a  very  soft  and  finished  appearance. 


CHAPTER  XXXVI. 

VARNISHING  AND   LACKERING. 

SECT.  I. — PREPARATION  OF  THE  VARNISHES. 

THE  varnishes  are  solutions  of  the  various  resins,  but  which  are 
by  varnish  makers  commonly  called  gums,  and  those  principally 
employed  are  amber,  anime,  copal,  lac,  sandarac,  mastic,  damar, 
and  common  resin,  dissolved  in  linseed  oil,  turpentine,  wood 
naphtha,  or  spirits  of  wine.  The  varnishes  are  all  applied  to  the 
surfaces  of  the  woods,  metals,  or  other  materials,  while  in  the 
fluid  state,  like  a  thin  paint,  and  the  solvent  is  afterwards 
evaporated,  leaving  a  thin  glassy  coat  of  the  different  resins  as  a 
defence  from  the  action  of  the  atmosphere,  or  from  slight 
friction. 

Sometimes  the  resins  are  used  separately,  at  other  times  two 
or  more  are  combined  in  the  same  varnish,  and  in  like  manner 
the  solvents  are  sometimes  employed  singly,  and  at  other  times 
are  combined,  according  to  the  qualities  required  in  the  varnish. 

The  durability  of  the  varnishes  is  of  course  mainly  dependent 
upon  the  comparative  insolubility  of  the  resins,  their  hardness, 
toughness,  and  permanence  of  colour.  In  these  respects  amber 
excels  all  other  resins  used  for  varnishes;  it  resists  the  action 
of  all  ordinary  solvents,  and  can  only  be  dissolved  for  making 
varnish  by  fusion  at  a  high  temperature;  it  is  hard  and  mode- 
rately tough,  and  its  colour  is  but  little  influenced  by  the  atmos- 
phere ;  but  unless  very  carefully  selected,  it  is  too  yellow  for 
delicate  works  of  light  colours.  Amber  is,  however,  but  little 
used  in  making  varnishes,  principally  on  account  of  its  high 
price,  but  partly  because  the  varnish  dries  slowly,  and  does  not 
attain  its  full  hardness  for  many  weeks. 

Anime  is  nearly  as  insoluble  and  hard  as  amber,  and  the  best 
is  of  a  very  pale  colour  ;  but  it  is  not  nearly  so  tough  as  amber. 


1375  AMEER,    ANIME,     AND    COPAL. 


The  varnishes  made  from  anime  dry  quickly,  but  are  very  liable 
to  crack,  and  the  colour  becomes  deeper  by  exposure  to  light 
and  air.  Anime  is,  however,  extensively  used  in  making  oil 
varnishes,  and  most  of  those  called  copal  varnishes  contain  a 
considerable  proportion  of  anime,  which  is  substituted  principally 
on  account  of  its  quick  drying  qualities. 

Copal  is  next  in  durability  to  amber;  when  very  carefully 
selected  it  is  almost  colourless,  and  becomes  rather  lighter  by 
exposure ;  it  is  more  easily  dissolved  by  heat  than  either  amber 
or  anime,  and  although  softer  than  these  resins,  is  too  hard  to 
be  scratched  by  the  nail.  Copal  is,  therefore,  a  most  excellent 
material  for  varnish,  and  numerous  attempts  have  been  made  to 
employ  it  as  the  basis  of  a  spirit  varnish,  but  hitherto  with  only 
partial  success.  Pure  alcohol  has  little  effect  on  copal ;  with 
the  addition  of  a  small  quantity  of  camphor,  the  greater  portion  of 
the  copal  is  dissolved,  but  the  camphor  impairs  the  durability  of 
the  varnish.  Copal  may  be  perfectly  dissolved  by  ether,  but 
this  spirit  evaporates  too  rapidly  to  allow  of  the  varnish  being 
uniformly  applied.  The  essential  oils  of  spruce  and  lavender 
have  been  occasionally  employed  as  solvents  of  copal,  but  not 
with  sufficient  success  to  warrant  its  general  adoption  in  spirit 
varnishes. 

Amber,  anime,  and  copal  are  therefore  usually  dissolved  for 
making  varnish  by  fusing  the  gum,  and  adding  linseed  oil  heated 
nearly  to  the  boiling  point.  They  are  then  amalgamated  by 
stirring  and  boiling,  and  the  varnish  is  reduced  to  the  required 
degree  of  fluidity  by  the  addition  of  oil  of  turpentine.  They 
constitute  the  more  important  of  what  are  called  oil  varnishes, 
are  the  most  durable  of  all,  possess  considerable  brilliancy,  and 
are  sufficiently  hard  to  bear  polishing.  They  are  therefore 
employed  for  works  of  the  best  quality,  that  are  exposed  to  the 
weather  or  to  much  friction,  as  coaches,  house  decorations,  and 
japanning. 

Lac  and  sandarac  are  more  soluble  than  the  above  resins,  and 
are  generally  dissolved  in  spirits  of  wine;  but  sometimes  the 
pyroligneous  spirit,  commonly  known  as  vegetable  naphtha,  is  em- 
ployed as  a  cheaper  substitute.  These  resins  constitute  the 
basis  of  what  are  called  spirit  varnishes,  and  are  employed 
principally  for  delicate  objects  not  exposed  to  the  weather,  such 
as  cabinet  and  painted  works. 


LAC,    SANDARAC,    MASTIC,    AND    RESIN.  1376 

Lac  is  much  harder  and  more  durable  than  sandarac,  and  is 
the  basis  of  most  lackers  for  hardwood  and  metal,  and  also  of 
the  so  called  French  polish.  Of  the  three  varieties,  stick  lac, 
seed  lac,  and  shell-lac,  the  latter  is  the  most  free  from  colour, 
and  the  most  soluble;  it  is  therefore  almost  exclusively  used  in 
making  varnishes  and  lackers ;  but  the  palest  shell-lac  contains 
a  considerable  quantity  of  colouring  matter,  that  renders  it 
inadmissible  for  varnishing  works  of  a  light  colour.  In  addition, 
shell-lac  also  contains  a  small  quantity  of  wax,  and  other  matters, 
that  are  only  imperfectly  soluble  in  spirits  of  wine,  and  therefore 
give  a  cloudy  appearance  to  the  varnish,  but  which  is  not  of  great 
importance  in  varnishing  dark  coloured  works,  and  may  be  in 
great  measure  avoided  by  making  the  solution  without  heat,  and 
allowing  the  more  insoluble  portions  time  to  be  precipitated. 

Sandarac  is  softer  and  less  brilliant  than  shell-lac,  but  is  much 
lighter  in  colour,  it  is  therefore  used  for  making  a  pale  varnish 
for  light  coloured  woods,  and  other  works  for  which  the  dark 
colour  of  shell-lac  would  be  unsuited.  When  hardness  is  of  greater 
importance  than  paleness,  a  portion  of  shell-lac  is  added,  but 
when  paleness  and  brilliancy  are  required,  a  small  quantity  of 
mastic  is  added.  When  the  varnish  is  required  to  be  polished, 
Venice  turpentine  is  added  to  give  sufficient  thickness  or  body. 

Mastic  is  softer  than  any  of  the  resins  previously  mentioned, 
and  is  dissolved  either  in  spirits  of  wine  or  oil  of  turpentine,  the 
latter  is  most  generally  used  on  account  of  it  cheapness.  With 
either  of  these  solvents  mastic  makes  a  varnish  of  a  very  pale 
colour,  that  is  brilliant,  works  easily,  and  flows  better  on  the 
surface  to  which  it  is  applied  than  most  other  varnishes.  It  is 
also  tolerably  flexible,  and  may  be  easily  removed  by  friction 
with  the  hand ;  it  is  therefore  much  used  for  varnishing  paintings, 
and  other  delicate  works. 

Damar  is  easily  dissolved  in  oil  of  turpentine,  and  when  care- 
fully selected  is  almost  colourless ;  it  makes  a  softer  varnish  than 
mastic;  the  two  combined  however  form  an  almost  colourless 
varnish,  moderately  hard  and  flexible,  and  well  .suited  for  maps 
and  similar  purposes. 

Common  resin  is  generally  dissolved  either  in  turpentine  or 
linseed  oil  with  heat.  Varnish  made  with  resin  is  hard  and 
brittle,  but  brilliant,  and  is  principally  employed  to  make  cheap 
varnishes  for  common  purposes  in  house  painting,  toys,  and 


1377  CLARIFYING    AND    BOILING    LINSEED    OIL. 


; 


cabinet  work.  It  is  also  added  to  other  varnishes  in  order  to 
improve  their  brilliancy,  but  it  should  be  added  in  small  quantities 
only,  as  a  large  proportion  of  resin  renders  the  varnishes  brittle. 

Linseed  oil  is  extensively  employed  as  a  vehicle  for  the  harder 
resins,  to  which  it  imparts  softness  and  toughness,  but  causes  the 
varnish  to  dry  slowly,  and  unless  the  oil  is  of  the  purest  and 
palest  quality,  well  clarified,  and  carefully  combined  with  the 
resin,  without  excess  of  heat,  it  materially  darkens  the  colour  of 
the  varnish  when  first  made,  and  it  is  also  liable  to  become 
darker  by  age  after  it  is  applied.  Linseed  oil  intended  for  the 
best  varnishes  is  clarified  by  gradually  heating  it*in  a  copper  pot 
so  as  to  bring  it  nearly  to  the  boiling  point  in  about  two  hours  ; 
it  is  then  skimmed  and  simmered  for  about  three  hours  longer, 
when  dried  magnesia,  in  the  proportion  of  about  one  quarter  of 
an  ounce  to  every  gallon  of  oil,  is  gradually  introduced  by 
stirring;  the  oil  is  then  boiled  for  about  another  hour,  and  after- 
wards suffered  to  cool  very  gradually.  It  is  then  removed  into 
leaden  or  tin  cisterns,  and  allowed  to  stand  for  at  least  three 
months,  during  which  the  magnesia  combines  with  the  impurities 
of  the  oil  and  carries  them  to  the  bottom,  and  the  clarified  oil  is 
taken  from  the  top  of  the  cistern  as  it  is  required  without 
disturbing  the  lower  portion,  and  the  settlings  are  reserved  for 
black  paint.  A  pale  drying  oil  may  also  be  made  as  above,  by 
substituting  for  the  magnesia,  white  copperas  and  sugar  of  lead, 
in  the  proportions  of  two  ounces  of  each  to  every  gallon  of  oil. 

Linseed  oil  when  rendered  drying,  by  boiling  and  the  addition 
of  litharge  and  red  lead,  is  sometimes  used  alone  as  a  cheap 
extempore  varnish.  In  boiling  linseed  oil,  it  is  heated  gradually 
to  bring  it  to  the  boiling  point  in  about  two  hours ;  it  is  then 
skimmed,  and  well  dried  litharge  and  red  lead,  in  the  proportion 
of  about  three  ounces  of  each  to  every  gallon  of  oil,  are  slowly 
sprinkled  in,  and  the  whole  is  boiled  and  gently  stirred  for  about 
three  hours,  or  until  it  ceases  to  throw  up  any  scum,  or  emit 
much  smoke.  It  is  then  frequently  tested  by  dipping  the  end  of 
a  feather  into  it,  and  when  the  end  of  the  feather  is  burnt  off,  or 
curls  up  briskly,  the  oil  is  considered  to  be  sufficiently  boiled, 
and  is  allowed  to  cool  very  slowly,  during  which  the  principal 
portion  of  the  driers  settle  to  the  bottom.  The  oil  is  afterwards 
deposited  in  leaden  cisterns  screened  from  the  sun  and  air. 
When  the  oil  is  required  to  be  as  pale  as  possible,  dried  white 


OJL    OF    TURPENTINE    AND    ALCOHOL.  1378 

lead,  sugar  of  lead,  and  white  copperas  are  employed  instead  of 
the  litharge  and  red  lead. 

Oil  of  turpentine  is  employed  as  a  vehicle  for  most  of  the  resins, 
the  oil  varnishes  being  generally  thinned  with  hot  oil  of  turpen- 
tine. Mastic,  damar,  and  common  resin  are  generally  made  into 
varnishes  by  dissolving  them  in  oil  of  turpentine  alone,  either 
cold  or  with  very  moderate  warmth.  Varnishes  made  with  tur- 
pentine only,  dry  quicker  than  those  made  with  oil,  and  are  paler 
coloured,  but  not  so  tough  and  durable.  Turpentine  varnishes 
hold  an  intermediate  position  between  oil  and  spirit  varnishes, 
and  are  employed  principally  on  account  of  their  cheapness  and 
flexibility.  Turpentine  varies  considerably  in  quality,  and  is 
greatly  improved  by  age;  that  intended  for  varnish  should  be  of 
the  best  quality,  clear  and  limpid,  and  be  kept  for  many  months, 
or  even  years,  before  it  is  used ;  and  when  employed  alone,  as 
for  mastic  varnish,  care  should  be  taken  that  it  is  not  passed 
through  an  oily  measure,  as  is  frequently  the  case  in  procuring 
small  quantities. 

Alcohol,  or  spirits  of  wine,  is  employed  for  dissolving  sandarac 
and  shell  lac,  to  make  the  white  and  brown  hard  spirit  varnishes, 
and  lacker  for  hardwood  or  brass,  and  also  French  polish.  The 
varnishes  made  with  alcohol  dry  much  quicker,  harder,  and  more 
brilliant  than  those  made  with  turpentine  ;  but  if  the  spirit  con- 
tains more  than  a  minute  proportion  of  water,  it  will  scarcely 
dissolve  the  resins,  and  when  the  varnish  is  applied,  a  very  slight 
degree  of  moisture  in  the  atmosphere  will  cause  the  resins  to  be 
precipitated  from  the  solution,  giving  the  varnish  a  dull,  cloudy, 
or  milky  appearance.  It  is  therefore  of  the  first  importance  in 
making  spirit  varnishes  to  procure  the  alcohol  as  pure  as  possible. 

Ordinary  spirits  of  wine,  however,  always  contains  a  consi- 
derable proportion  of  water,  and  is  commonly  tested  for  varnish 
purposes  by  saturating  a  slip  of  writing  paper  with  the  spirit, 
which  is  then  ignited,  and  if  the  flame  of  the  spirit  communicates 
to  the  paper,  and  the  whole  is  burned,  the  spirit  is  considered  to 
be  sufficiently  good.  But  if,  as  frequently  happens,  the  paper 
should  be  so  far  saturated  with  the  water  remaining  from  the 
evaporation  of  the  spirit  as  to  prevent  its  burning,  the  spirit  is 
rejected  as  unfit  for  varnish  purposes. 

Weighing  is,  however,  a  far  more  exact  test,  the  specific 
gravity  of  absolutely  pure  alcohol  being  nearly  *8,  at  a  tempera- 

VOL.  III.  A  A 


1379  CONCENTRATING    ALCOHOL. 


ture  of  60°,  it  may  be  easily  tested  by  weighing  10  ounces  of 
distilled  water  in  a  glass  bottle,  marking  a  line  on  the  bottle  to 
show  the  exact  height  of  the  water,  and  afterwards  filling  the 
bottle  with  spirit  to  the  same  height,  and  weighing  it,  when  the 
excess  over  8  ounces  will  show  the  proportion  of  water  with  tole- 
rable accuracy ;  and  should  it  not  exceed  8£  ounces,  it  may  be 
considered  to  be  of  very  good  quality,  spirit  being  frequently 
used  for  making  varnish  when  its  specific  gravity  is  equal  to  '85. 

Nearly  pure  alcohol  may  be  obtained  from  ordinary  spirits  of 
wine,  by  adding  about  one-third  its  weight  of  well-dried  car- 
bonate of  potash,  agitating  the  bottle,  and  then  allowing  it  to 
stand  for  ten  or  twelve  hours,  during  which  time  the  potash  will 
absorb  much  of  the  water  from  the  spirit  and  fall  to  the  bottom ; 
the  spirit  may  then  be  poured  off,  and  fresh  alkali  added,  and 
the  process  repeated  until  the  potash  remains  quite  dry,  and  the 
alcohol  is  then  to  be  freed  from  the  small  portion  of  potash  which 
it  holds  in  solution  by  distillation  in  a  water  bath. 

A  far  more  convenient  method  of  concentrating  spirit  of  wine 
for  varnish  making,  is  that  discovered  by  Sommering,  founded 
upon  the  property  of  ox  bladders,  to  allow  water  to  pass  through 
and  evaporate  out  of  them,  but  not  permit  alcohol  to  transpire, 
or  only  in  a  slight  degree.  According  to  Sommering,  as  quoted 
by  Ure,  "  we  should  take  for  this  purpose  the  bladder  of  an  ox 
or  calf,  soak  it  for  some  time  in  water,  then  inflate  it  and  free  it 
from  the  fat  and  the  attached  vessels,  which  is  also  to  be  done  to 
the  other  surface,  by  turning  it  inside  out.  After  it  is  again 
inflated  and  dried,  we  must  smear  over  the  outer  side  twice,  and 
the  inner  side  four  times,  with  a  solution  of  isinglass,  by  which 
its  texture  is  made  closer,  and  the  concentration  of  the  alcohol 
goes  on  better.  A  bladder  so  prepared  may  serve  more  than  a 
hundred  times.  It  must  be  charged  with  the  spirits  to  be  con- 
centrated, leaving  a  small  space  vacant ;  it  is  then  to  be  tightly 
bound  at  the  mouth,  and  suspended  in  a  warm  situation  at  a 
temperature  of  122°  Fahr.,  over  a  sand  bath  or  in  the  neighbour- 
hood of  an  oven.  Weak  spirit  loses  its  water  quicker  than 
strong,  but  in  from  six  to  twelve  hours  the  alcohol  may  be  con- 
centrated when  a  suitable  heat  is  employed.  Alcohol  may  also 
be  strengthened,  as  Sommering  has  ascertained,  when  the  vessel 
that  contains  the  spirit  is  bound  over  with  a  bladder  which  does 
not  come  into  contact  with  the  liquor." 


PREPARATION    OP    OIL    VARNISHES.  1380 

The  coating  of  the  bladder  with  the  solution  of  isinglass 
appears,  however,  not  to  be  essential  to  the  success  of  the  method 
for  varnish  purposes,  as,  upon  experiment  with  an  unprepared 
bladder,  spirits  of  wine  of  s.  p.  8'54  was  brought  in  a  few  hours 
to  s.  p.  8*11,  showing  it  to  contain  about  95  per  cent,  of  pure 
alcohol. 

Naphtha,  or  the  spirit  procured  by  distillation  from  pyror 
lignous  acid,  and  commonly  known  as  vegetable  or  wood  naphtha, 
is  frequently  employed  instead  of  spirits  of  wine  for  making 
cheap  varnishes.  It  dissolves  the  resins  more  readily  than 
ordinary  spirit  of  wine,  but  the  varnish  is  less  brilliant,  and  the 
smell  of  the  naphtha  is  very  offensive.  It  is  therefore  never 
employed  for  the  best  works, 

The  preparation  of  oil  varnishes  requires  the  application  of 
considerable  heat,  and  owing  to  this  and  the  highly  inflammable 
nature  of  the  materials,  the  process  is  attended  with  considerable 
risk  of  setting  the  building  on  fire.  The  process  should  therefore 
always  be  conducted  in  detached  buildings  constructed  expressly 
for  the  purpose.  Owing  partly  to  the  necessity  for  this  precau- 
tion, and  the  circumstance  that  oil  varnishes  are  greatly  improved 
by  being  kept  in  leaden  cisterns  for  some  months  before  they  are 
used,  the  preparation  of  oil  varnish  is  carried  on  almost  exclu- 
sively as  a  separate  manufacture,  the  details  of  which  are  greatly 
varied  and  are  mostly  kept  secret. 

In  1833,  Mr.  J.  Wilson  Neale,  a  varnish  manufacturer  of 
thirty  years'  experience,  received  a  gold  medal  from  the  Society 
of  Arts  for  a  very  complete  description  of  his  method  of  making 
oil  and  other  varnishes,  published  in  Vol.  XLIX.  of  the  Society's 
Transactions,  from  which  the  following  directions  for  the  prepa- 
ration of  oil  varnishes  in  small  quantities  have  been  extracted  : — 

"  The  copper  pot  employed  to  make  the  varnish,  is  called  &  gum- 
pot,  and  measures  about  2  feet  9  inches  in  height,  and  9  J  inches  dia- 
meter externally.  The  bottom  is  hammered  out  of  a  single  piece 
of  copper,  and  fashioned  like  a  hat  without  a  brim ;  it  is  about 
9  inches  deep,  and  three-eighths  of  an  inch  in  thickness.  The 
upper  part  of  the  pot  is  formed  as  a  cylinder,  of  sheet  copper, 
about  2  feet  2  inches  in  height,  and  of  sufficient  diameter  to  slip 
about  2  inches  over  the  upper  edge  of  the  bottom  piece,  to  which 
it  is  firmly  ri vetted.  A  wide  flange  of  copper,  to  support  the  pot, 
is  also  fixed  just  beneath  the  lower  edge  of  the  cylinder,  and  a 

A  A2 


1381  APPARATUS    USED    IN    MAKING   OIL    VARNISHES. 


strong  iron  hoop  is  fixed  a  little  above  the  line  of  the  rivets,  to 
serve  for  the  attachment  of  the  horizontal  handle,  which  is  made 
as  a  nearly  straight  rod,  one  inch  square,  flattened  at  the  end, 
and  2  feet  8  inches  long. 

"  The  stirrer  is  a  copper  rod  about  three-quarters  of  an  inch 
diameter,  and  3  feet  6  inches  long,  flattened  at  the  one  end  to 
1J  inch  in  breadth  for  about  8  inches  in  length,  and  fitted  at  the 
opposite  end  with  a  short  wooden  handle. 

"  The  ladle,  which  should  contain  about  two  quarts,  is  also  of 
copper  beaten  out  of  the  solid,  and  rivetted  to  a  handle  of  the 
same  metal,  3  feet  6  inches  long,  and  fitted  with  a  wooden  handle 
like  the  stirrer. 

"  The  copper  jack,  for  pouring  hot  oil  into  the  gum-pot,  is 
made  in  the  form  of  a  pitcher,  with  a  large  handle  and  a  wide 
spout ;  it  contains  two  gallons.  The  brass  or  copper  sieve,  for 
straining  the  varnish,  is  about  9  inches  diameter,  and  contains 
sixty  meshes  to  the  inch.  The  copper  funnel,  for  straining  the 
boiling  varnish,  is  large  enough  to  receive  the  sieve,  and  should 
be  well  made  with  lapped  seams,  as  solder  would  be  melted  with 
the  heat. 

"  The  tin  pouring  pot,  to  hold  three  gallons,  is  formed  exactly 
like  a  garden  watering-pot,  only  smaller  at  the  spout,  and  with- 
out any  rose.  This  is  never  to  be  used  for  any  purpose  except 
pouring  oil  of  turpentine  into  the  varnish. 

"  A  small  broom,  termed  '  a  swish,"1  used  for  washing  out  the 
gum-pot  every  time  after  use,  is  made  from  cuttings  of  cane  tied 
to  a  small  handle  like  a  hearth-broom ;  the  head  is  5  inches  long, 
and  5  inches  round.  This  should  be  washed  in  turpentine,  and 
kept  very  clean. 

"  A  three-footed  iron  trevet,  with  a  circular  top,  is  employed 
to  support  the  gum-pot.  The  feet  of  the  trevet  are  about  16 
inches  in  height,  and  spread  wider  at  the  bottom  than  the  top, 
which  is  made  of  such  a  size  that  the  pot  will  fit  easily  into  it,  the 
flange  resting  on  the  top. 

c*  An  ash-bed  should  be  prepared  near  the  fire,  upon  which  to 
place  the  gum-pot  when  the  varnish  is  ready  for  mixing,  or  that 
the  heat  is  becoming  too  great.  This  is  prepared  by  sifting 
some  dry  ashes  through  a  fine  sieve,  to  make  a  smooth  layer 
about  1J  inch  thick,  and  a  little  larger  than  the  bottom  of  the 
gum-pot. 


MAKING    OIL    VARNISHES.  1382 

"  Place  the  trevet  in  a  hollow  in  a  field,  yard,  garden,  or  out- 
house, where  there  can  be  no  danger  from  fire  ;  raise  a  temporary 
fire-place  round  the  trevet  with  loose  bricks,  after  the  same 
manner  that  plumbers  make  their  furnaces  ;  then  make  up  a  good 
fire  with  either  coke,  coal,  or  wood  charcoal,  which  is  far  pre- 
ferable ;  let  the  fire  burn  to  a  good  strong  heat,  set  on  the  gum- 
pot  with  3  Ib.  of  gum  copal ;  observe  that  if  the  fire  surround  the 
gum-pot  any  higher  inside  than  the  gum,  it  is  in  great  danger  of 
taking  fire.  As  soon  as  the  gum  begins  to  fuse  and  steam,  put 
in  the  copper  stirrer,  and  keep  cutting,  dividing,  and  stirring  the 
gum  to  assist  its  fusion  ;  and  if  it  feels  lumpy  and  not  fluid,  and 
rises  to  the  middle  of  the  pot,  lift  it  from  the  fire  and  set  it  on 
the  ash-bed,  and  keep  stirring  until  it  goes  down  (meantime  let 
the  fire  be  kept  briskly  up) ;  then  set  on  the  gum-pot  again,  and 
keep  stirring  until  the  gum  appears  fluid  like  oil,  which  is  to  be 
known  by  lifting  up  the  stirrer  so  far  as  to  see  the  blade. 
Observe,  that  if  the  gum  does  not  appear  quite  fluid  as  oil,  carry 
it  to  the  ash-bed  whenever  it  rises  to  the  middle  of  the  pot,  and 
stir  it  down  again  (keep  up  a  brisk  fire),  put  on  the  pot  and  keep 
stirring  until  the  gum  rises  above  the  blade  of  the  stirrer;  call 
out  to  the  assistant,  *  be  ready  ! '  He  is  then,  with  both  hands, 
to  lay  hold  of  the  copper  pouring-jack,  charged  with  (one  gallon) 
clarified  oil,  and  lean  the  spout  about  one  inch  and  a  half  over 
the  edge  of  the  gum-pot.  Let  him  keep  himself  firm,  steady, 
and  collected,  and  not  flinch,  spill,  or  pour  the  oil,  which  would 
perhaps  set  all  on  fire.  Observe,  when  the  gum  rises  within  five 
inches  of  the  pot-mouth,  call  out,  '  Pour ! '  The  assistant  is  then 
to  pour  in  the  oil  very  slowly  until  towards  the  last,  the  maker 
stirring  during  the  pouring. 

§"  If  the  fire  at  this  time  is  strong  and  regular,  in  about  eight 
ten  minutes  the  gum  and  oil  will  concentrate  and  become 
ite  clear :  this  is  to  be  tested  by  taking  a  piece  of  broken 
window  glass  in  the  left  hand,  and  with  the  right  lifting  up  the 
stirrer  and  dropping  a  portion  of  the  varnish  on  it ;  if  it  appears 
clear  and  transparent,  the  oil  and  gum  are  become  concentrated 
or  joined  together.  It  is  now  to  be  further  boiled  until  it  will 
string  between  the  finger  and  thumb :  this  is  known  by  once 
every  minute  dropping  a  portion  on  the  glass  and  taking  a  little 
between  the  forefinger  and  thumb  :  if  it  is  boiled  enough  it  will 
stick  strong,  and  string  out  into  fine  filaments,  like  bird-lime ; 


1383  MAKING    OIL    VARNISHES. 

but  when  not  boiled  enough,  it  is  soft,  thick,  and  greasy  without 
being  stringy.  The  moment  it  is  boiled  enough,  carry  it  from 
the  fire  to  the  ash-bed  where  let  it  remain  from  fifteen  to 
twenty  minutes,  or  until  it  is  cold  enough  to  be  mixed ;  have  at 
hand  a  sufficient  quantity  of  oil  of  turpentine  to  fill  the  pouring 
pot,  (2  gallons)  begin  and  pour  out  with  a  small  stream, 
gradually  increasing  it,  and  if  the  varnish  rises  rapidly  in  the 
pot,  keep  stirring  it  constantly  at  the  surface  with  the  stirrer  to 
break  the  bubbles,  taking  care  not  to  let  the  stirrer  touch  the 
bottom  of  the  pot,  for  if  it  should,  the  oil  of  turpentine  would 
be  in  part  converted  into  vapour,  and  the  varnish  would  run 
over  the  pot  in  a  moment :  therefore  during  the  mixing,  keep 
constantly  stirring  as  well  as  pouring  in  at  the  same  time. 
Have  also  a  copper  ladle  at  hand,  and  if  it  should  so  far  rise  as 
to  be  unmanageable,  let  the  assistant  take  the  ladle  and  cool  it 
down  with  it  lifting  up  one  ladleful  after  another,  and  letting  it 
fall  into  the  pot.  As  soon  as  the  varnish  is  mixed,  put  the 
varnish  sieve  in  the  copper  funnel  placed  in  the  carrying  tin, 
and  strain  the  varnish  immediately ;  empty  it  into  open  mouthed 
jars,  tins,  or  cisterns,  there  let  it  remain  to  settle,  and  the  longer 
it  remains  the  better  it  will  become.  Recollect  when  it  is  taken 
out,  not  to  disturb  or  raise  up  the  bottoms. 

"  Instead  of  the  ash-bed  a  circle  of  loose  bricks  four  courses 
high  may  be  erected  to  support  the  gum-pot.  The  bricks  are 
to  be  laid  so  that  when  the  gum-pot  is  set  within  it  will  rest 
securely  by  its  flange  with  the  bottom  about  six  inches  from  the 
ground.  Upon  this  brick-stand  set  the  pot  every  time  there  is 
occasion  to  carry  it  from  the  fire.  Near  the  stand  an  iron  trevet 
may  be  placed,  upon  which  to  turn  the  gum-pot  every  time  after 
it  is  washed  out,  as,  by  so  doing,  it  will  always  be  kept  clean 
and  cool  gradually,  for  by  cooling  rapidly  copper  oxidises  very 
quickly.  Near  the  trevet  have  the  swish  broom  and  also  a 
large  wide  tin  jack  or  other  vessel  to  receive  the  washings. 
Have  also  at  hand  a  copper  ladle,  and  a  tin  bottle  with  turpen- 
tine, for  washing  with  when  wanted. 

''  The  moment  the  maker  has  emptied  the  gum-pot,  throw  into 
it  half  a  gallon  of  turpentine,  and  with  the  swish  immediately 
wash  it  from  top  to  bottom,  and  instantly  empty  it  into  the  tin 
jack.  Afterwards  with  a  large  piece  of  woollen  rag  dipped  in 
puinice  powder,  wash  and  polish  every  part  of  the  inside  of  the 


in 

- 


MAKING    OIL    VARNISHES.  1384 

t,  performing  the  same  operation  on  the  ladle  and  stirrer; 
nee  them  with  the  turpentine  washings,  and  at  last  rince  them 
together  with  clean  turpentine,  which  also  put  to  the  washings; 
ipe  dry  with  a  clean  soft  rag,  the  pot,  ladle,  stirrer  and  funnel, 
d  lay  the  sieve  so  as  to  be  completely  covered  with  turpentine 
hich  will  always  keep  it  from  gumming  up. 
"  Eight  pounds  of  Copal  takes  in  general  from  sixteen  to 
enty  minutes  in  fusing,  from  the  beginning  till  it  gets  clear 
ike  oil;  but  the  time  depends  very  much  on  the  heat  of  the 
fire  and  the  attention  of  the  operator.  During  the  first  twelve 
inutes  while  the  gum  is  fusing  the  assistant  must  look  to  the 
il,  which  is  to  be  heated  at  a  separate  fire  in  a  copper  pot, 
large  enough  to  contain  double  the  quantity  required.  The  oil 
d  be  brought  to  a  smart  simmer,  for  it  ought  neither  to  be 
o  hot  nor  too  cold,  but  in  appearance  beginning  to  boil,  which 
e  assistant  is  strictly  to  observe,  and  when  ready,  call  to  the 
aker,  then  immediately  each  take  hold  of  one  handle  of  the 
iling  pot  and  carry  it  to  the  ash-bed,  the  maker  instantly 
turning  to  the  gum- pot,  while  the  assistant  ladles  the  hot  oil 
to  the  copper  pouring  jack,  bringing  it  and  placing  it  at  the 
k  of  the  gum-pot  until  wanted. 

A  thick  piece  of  old  carpet,  free  from  holes,  should  be  kept 
hand  in  case  the  gum-pot  should  take  fire  ;  should  this  happen, 
t  the  assistant  throw  the  piece  of  carpet  quickly  over  the 
zing  pot,  holding  it  down  all  round  the  edges  ;  and  in  a  few 
nutes  the  fire  will  be  smothered. 

After  the  oil  has  been  mixed  with  the  gum,  a  brisk,  strong 
e  should  be  kept  up,  until  a  scum  or  froth  rises  and  covers  all 
e  surface  of  the  contents,  when  it  will  begin,  to  rise  rapidly, 
bserve  when  it  rises  about  two-thirds  the  height  of  the  pot, 
rry  it  from  the  fire,  and  set  it  on  the  ash-bed,  or  brick- stand, 
ir  it  down  again ;  and  if  driers  are  to  be  added,  scatter  in  a 
w  by  a  little  at  a  time ;  keep  stirring,  and  if  the  frothy  head 
es  down,  put  the  pot  on  the  fire,  and  introduce  gradually  the 
remainder  of  the  driers,  always  carrying  the  pot  to  the  ash-bed 
when  the  froth  rises  about  two-thirds  the  height  of  the  pot.     In 
general,  if  the  fire  be  good,  all  the  time  a  pot  requires  to  boil 
from  the  time  of  the  oil  being  poured  in,  is  about  three-and-a- 
half  or  four  hours  ;  but  time  is  no  criterion  for  a  beginner  to 
judge  by,  as  it  may  vary  according  to  the  weather,  the  quality 


1385  FINE    COPAL    VARNISHES. 

of  the  ingredients,  or  the  heat  of  the  fire ;  therefore,  about  the 
third  hour  of  boiling,  try  it  on  a  bit  of  glass,  and  keep  boiling  it 
until  it  feels  strong  and  stringy  between  the  fingers,  as  before 
mentioned. 

The  foregoing  directions  are,  with  very  little  differences,  to  be 
observed  in  making  all  sorts  of  copal  varnishes,  excepting  the 
quantities  of  oil,  gum,  &c.,  a  few  of  which  will  be  now  added. 

Copal  varnish  for  fine  paintings,  Sec.  Fuse  8  Ibs.  of  the  very 
cleanest  pale  African  gum  copal,  and,  when  completely  run  fluid, 
pour  in  two  gallons  of  hot  oil ;  let  it  boil  until  it  will  string  very 
strong ;  and  in  about  fifteen  minutes,  or  while  it  is  yet  very  hot, 
pour  in  three  gallons  of  turpentine,  got  from  the  top  of  a  cistern. 
Perhaps  during  the  mixing  a  considerable  quantity  of  the  turpen- 
tine will  escape,  but  the  varnish  will  be  so  much  the  brighter, 
transparent,  and  fluid ;  and  will  work  freer,  dry  quickly,  and  be 
very  solid  and  durable  when  dry.  After  the  varnish  has  been 
strained,  if  it  is  found  too  thick,  before  it  is  quite  cold,  heat  as 
much  turpentine  and  mix  with  it  as  will  bring  it  to  a  proper 
consistence. 

Artist's  virgin  copal.  From  a  select  parcel  of  scraped  African 
gum  copal,  before  it  is  broke,  pick  out  the  very  fine  transparent 
pieces,  which  appear  round  and  pale,  like  drops  of  crystal ;  break 
these  very  small ;  dry  them  in  the  sun,  or  by  a  very  gentle  fire. 
Afterwards,  when  cool,  bruise  or  pound  them  into  a  coarse 
powder ;  then  procure  some  broken  bottles  or  flint-glass,  and 
boil  the  same  in  soft  water  and  soda,  then  bruise  it  into  a  coarse 
powder,  like  the  gum ;  boil  it  a  second  time,  and  strain  the 
water  from  it,  washing  it  with  three  or  four  waters,  that  it  may 
be  perfectly  clean  and  free  from  grease  or  any  impurity,  dry  it 
before  the  fire,  or  upon  a  plate  set  in  an  oven.  When  thoroughly 
dry,  mix  2  Ibs.  of  the  powdered  glass  with  3  Ibs.  of  the  powdered 
copal ;  after  mixing  them  well,  put  them  into  the  gum-pot,  and 
fuse  the  gum ;  keep  stirring  all  the  time  ;  the  glass  will  prevent 
the  gum  from  adhering  together,  so  that  a  very  moderate  fire 
will  cause  the  gum  to  fuse.  When  it  appears  sufficiently  run, 
have  ready  three  quarts  of  clarified  oil,  very  hot,  to  pour  in. 
Afterwards  let  it  boil  until  it  strings  freely  between  the  fingers. 
Begin  and  mix  it  rather  hotter  than  if  it  were  body  varnish,  for, 
as  there  is  but  a  small  quantity,  it  will  be  sooner  cold ;  pour  in 
five  quarts  of  old  turpentine,  strain  it  immediately,  and  pour  it 


CABINET    AND    BODY    VARNISHES.  1386 

into  an  open  jar,  or  large  glass  bottle ;  expose  it  to  the  air  and 
light,  but  keep  it  both  from  the  sun  and  moisture  until  it  is  of  a 
sufficient  age  for  use.  This  is  the  finest  copal  varnish  for  fine 
paintings. 

Cabinet  varnish.  Fuse  7  Ibs.  of  very  fine  African  gum  copal, 
when  well  dissolved  pour  in  half  a  gallon  of  pale  clarified  oil; 
and  when  clear  mix  with  it  three  gallons  of  turpentine ;  after- 
wards strain  it,  and  put  it  aside  for  use.  This,  if  properly  boiled, 
will  dry  in  ten  minutes ;  but  if  too  strongly  boiled,  will  not  mix 
at  all  with  the  turpentine  ;  and  sometimes^  when  boiled  with  the 
turpentine  will  mix,  and  yet  refuse  to  amalgamate  with  any 
other  varnish  less  boiled  than  itself;  therefore  it  requires  a 
nicety  which  is  only  to  be  learned  from  practice.  This  varnish 
is  very  apt  to  chill  all  other  oil  varnishes  to  which  it  may  be 
added,  and  is  principally  employed  as  a  quick  drying  varnish  for 
the  occasional  use  of  japanners,  cabinet  and  coach  painters. 
Cabinet  varnish  is,  however,  more  generally  made  with  anime 
than  copal. 

Best  body  copal  varnish,  used  for  the  body  parts  of  coaches  and 
other  objects  intended  for  polishing.  Fuse  8  Ibs.  of  fine  African 
gum  copal,  add  2  gallons  of  clarified  oil ;  boil  it  very  slowly  for 
four  or  five  hours,  until  quite  stringy,  and  mix  it  off  with  3% 
gallons  of  turpentine. 

The  above  varnishes  being  made  of  the  finest  copal  without 
driers  are  the  palest  and  best  of  the  copal  varnishes,  possessing 
great  fluidity  and  pliability,  but  they  are  rather  slow  in  drying, 
and  retain  for  months  so  much  softness  that  they  will  not  polish 
well,  until  they  give  out  a  moisture  and  become  hard ;  after 
which  they  are  very  durable.  When  paleness  is  not  of 
primary  importance  a  second  quality  of  gum  is  used,  and  when 
the  varnish  is  required  to  dry  quickly,  sugar  of  lead  or  white 
copperas  are  introduced  as  driers,  either  singly  or  combined,  in 
the  proportion  of  from  half  a  pound  to  one  pound  to  each  of  the 

Kiantities  above  quoted,  but  driers  are  always  injurious  to  the 
lour,  brilliancy  and   durability  of  varnishes.     When  a  varnish 
required  that  will  dry  quick  and  hard  without  driers,  gum 
lime  is  substituted  for  the  copal,  but  it  is  less  durable  and 
becomes  darker  by  age.      Frequently  anime  varnish  is  mixed 
with  copal  varnish  by  the  maker  while  both  are  hot,  in  different 
proportions    according    to   the   quality   required ;    one   pot   of 


1387  CARRIAGE,    WAINSCOT    AND    AMBER    VARNISHES. 

anime  to  two  of  copal  being  used  for  a  moderately  quick 
drying  body  varnish  of  good  quality ;  and  two  pots  of  anime  to 
one  of  copal  for  a  quicker  drying  body  varnish  of  common  quality. 

Carriage  varnish  is  made  much  the  same  as  common  body 
varnish,  except  that  to  8  Ibs.  of  gum  of  second  quality  to  about 
2£  gallons  of  oil,  and  5|  gallons  of  turpentine  are  used  with 
driers.  This  varnish  is  boiled  until  very  stringy,  and  is  used  for 
the  wheels  and  under  framework  of  coaches  and  other  objects 
not  requiring  to  be  polished ;  it  is  intermediate  in  quality 
between  body  varnish  and  the  following. 

Wainscot  varnish  consists  of  8  Ibs.  of  second  quality  of  gum 
anime,  3  gallons  of  clarified  oil,  \  Ib.  of  litharge,  £  lb.  of  dried 
sugar  of  lead,  \  lb.  of  copperas,  well  boiled  until  it  strings  very 
strong  and  mixed  with  5£  gallons  of  turpentine.  This  varnish 
dries  quickly  and  is  principally  used  for  house  painting  and 
japanning.  When  a  darker  varnish  is  required  as  for  mahogany 
a  small  portion  of  gold  size  may  be  mixed  with  it« 

Pale  amber  varnish.  Fuse  6  Ibs.  of  fine-picked  very  pale 
transparent  amber,  in  the  gum- pot,  and  pour  in  2  gallons  of 
hot  clarified  oil.  Boil  it  until  it  strings  very  strong.  Mix  with 
4  gallons  of  turpentine.  This  will  be  as  fine  as  body  copal, 
will  work  very  free,  and  flow  well  upon  any  work  it  is  applied 
to;  it  dries  slowly,  but  becomes  very  hard,  and  is  the  most 
durable  of  all  varnishes.  It  is  very  excellent  to  mix  in  copal 
varnishes  to  give  them  a  hard  and  durable  quality.  Amber 
varnish  is  however  but  little  used  on  account  of  its  expense. 

In  making  all  the  above  varnishes  it  should  be  observed,  that 
the  more  minutely  the  gum  is  fused,  the  greater  the  quantity 
and  the  stronger  the  produce.  The  more  regular  and  longer 
the  boiling  of  the  oil  and  gum  together  is  continued,  the  more 
fluid  or  free  the  varnish  will  extend  on  whatever  it  is  applied. 
When  the  mixture  of  oil  and  gum  is  too  suddenly  brought  to 
string  by  too  strong  a  heat,  the  varnish  requires  more  than  its 
just  proportion  of  turpentine  to  thin  it,  whereby  its  oily  and 
gummy  quality  is  reduced,  which  renders  it  less  durable; 
neither  will  it  flow  so  well  in  laying  on.  The  greater  proportioi 
of  oil  there  is  used  in  varnishes,  the  less  they  are  liable  to  crack, 
because  the  tougher  and  softer  they  are.  Increase  the  pro- 
portion of  gum  in  varnishes  the  thicker  the  stratum  required, 
and  the  firmer  they  will  set,  and  the  quicker  they  will  dry, 


PREPARATION  OF  SPIRIT  AND  TURPENTINE  VARNISHES.          1388 

All  body  varnishes,  or  those  intended  to  be  polished  should 
have  l£  Ibs.  of  gum  to  each  gallon  of  varnish  when  it  is  strained 
off  and  cold.  All  carriage  or  wainscot  varnishes,  or  those  not 
intended  to  be  polished  should  have  full  1  Ib.  of  gum  to  each 
gallon.  But  the  quantity  of  gum  required  to  bring  it  to  its 
proper  consistence,  depends  very  much  upon  the  degree  of 
boiling  it  has  undergone ;  therefore  when  the  gum  and  oil  have 
not  been  strongly  boiled  the  varnish  requires  less  turpentine  to 
thin  it,  and  when  boiled  stronger  than  usual  a  larger  proportion 
of  turpentine  is  required,  and  if  the  mixing  of  the  varnish  with 
the  turpentine  is  commenced  too  soon,  and  the  pot  is  not 
sufficiently  cool,  there  may  be  considerable  loss  by  evaporation. 

Copal  varnishes  should  be  made  at  least  three  months  before 
they  are  required  for  use,  and  the  longer  they  are  kept  the 
better  they  become,  but  when  it  is  necessary  to  use  the  varnishes 
before  they  are  of  sufficient  age,  they  should  be  left  thicker  than 
usual. 


In  the  preparation  of  spirit  and  turpentine  varnishes,  scarcely 
any  apparatus  is  required  ;  as,  generally  speaking,  the  process  is 
almost  limited  to  mixing  the  resins  and  solvent  together,  and 
agitating  the  whole  until  the  resin  is  thoroughly  dissolved. 
Heat  is  not  generally  necessary,  and  although  frequently  resorted 
to  in  order  to  facilitate  the  dissolution  of  the  resins,  in  most 
instances  only  a  moderate  degree  of  warmth  is  required,  and 
consequently  the  preparation  of  spirit  and  turpentine  varnishes  is 
far  more  manageable  than  that  of  oil  varnishes,  and  entails  much 
less  risk  of  accident. 

The  resins  should  be  thoroughly  free  from  moisture,  and  are 
generally  broken  into  small  pieces,  in  order  that  they  may  be 
dissolved  more  quickly,  and  all  impurities  are  carefully  picked 
out ;  after  which  the  finest  and  clearest  pieces  are  generally 
selected  and  set  aside  for  making  small  quantities  of  varnish  of 
a  superior  quality.  Sometimes,  with  the  view  of  expediting  the 
dissolution  of  the  resins,  they  are  finely  powdered  before  they  are 
added  to  the  solvent ;  but  in  this  case  it  is  necessary  that  the 
agitation  should  be  maintained  from  the  time  the  resin  is  added 
until  it  is  thoroughly  dissolved,  or  otherwise  it  is  liable  to 
agglutinate  into  one  mass'  that  is  afterwards  very  difficult  of 
solution. 


1389 


MAKING    SPIRIT    VARNISHES    WITHOUT    HEAT. 


In  making  turpentine  varnishes  without  heat,  in  quantities 
of  ten  or  twelve  gallons,  the  resin  and  turpentine  are  generally 
introduced  into  a  large  can  with  a  wide  mouth,  and  agitated  by 
stirring  with  a  stout  stick ;  a  number  of  wooden  pegs  or  nails 
are  mostly  driven  into  the  stick  near  the  lower  end  to  increase 
its  effect. 

Spirit  varnishes  are  generally  made  in  smaller  quantities,  and 
to  prevent  the  evaporation  of  the  spirit,  the  mouth  of  the  vessel 
is  mostly  closed  and  the  vessel  itself  is  agitated.  In  making 
quantities  of  four  to  eight  gallons,  the  resin  and  solvent  are 
sometimes  introduced  into  a  small  cask  capable  of  containing 
about  double  the  quantity,  and  mounted  to  revolve  on  central 
bearings  at  the  ends.  The  cask  is  made  to  revolve  either  with 
continuous  motion  by  a  winch-handle,  or  with  an  alternating 
motion,  by  means  of  a  cord  passed  around  the  barrel,  and  termi- 
nating in  a  cross  handle,  which  the  operator  pulls  to  give  motion 
to  the  barrel  in  the  one  direction,  and  the  momentum  of  which 
suffices  to  coil  up  the  cord  ready  for  the  following  pull,  which 
causes  the  barrel  to  revolve  in  the  opposite  direction,  and  so  on 
continually* 

Quantities  of  varnish,  not  exceeding  two  or  three  gallons,  are 
generally  agitated  in  a  tin  can,  rolled  backwards  and  forwards 
upon  a  bench  covered  with  an  old  carpet,  or  a  sack ;  but  what- 
ever method  is  adopted  for  the  agitation,  it  should  be  continued 
without  intermission  until  the  resin  is  sufficiently  dissolved,  to 
prevent  the  risk  of  its  becoming  agglutinated,  the  time  required 
for  which  depends  upon  the  solubility  of  the  resin,  and  the 
strength  of  the  spirit,  but  is  commonly  from  three  to  four  hours. 
The  further  agitation  for  the  thorough  solution  of  ;the  resin  may 
be  either  continuous  or  intermittent,  according  to  convenience, 
but  it  should  not  be  abandoned  until  the  solution  is  perfect ; 
and  when  it  is  judged  to  be  complete,  the  varnish  is  poured  into 
another  vessel  for  examination,  and  if  any  of  the  resin  is  not 
perfectly  dissolved,  the  whole  is  returned  to  the  vessel  for  fur- 
ther agitation.  When  the  resin  is  all  dissolved,  the  varnish  is 
allowed  to  stand  for  a  few  hours,  that  any  impurities  may  settle 
to  the  bottom,  and  the  clear  varnish  is  lastly  strained  through 
muslin  or  lawn  into  bottles,  and  allowed  to  stand  for  a  few  days 
before  use. 

Very  small  quantities  of  varnish  are  generally  made  in  gl 


MAKING    SPIRIT    VARNISHES    WITH    HEA1  1390 

bottles,  large  enough  to  contain  about  one-third  more  than  the 
quantity  introduced,  and  they  are  shaken  up  at  frequent  inter- 

Kls  ;  but  although  from  the  small  bulk  of  the  resin  it  cannot 
glutinate  into  so  insoluble  a  mass  as  when  larger  quantities  are 
made,  still  when  the  agitation  is  intermitted,  several  days  are 
frequently  required  before  the  resins  are  entirely  dissolved,  as 
the  solution  depends  more  upon  the  amount  of  agitation  than 
the  length  of  time  the  resins  are  submitted  to  the  action  of 
the  solvent. 

Sometimes,  with  the  view  of  preventing  the  agglutination,  and 
facilitating  the  dissolution  of  the  resins,  coarsely  pounded  glass 
is  introduced  with  the  resin  and  solvent ;  in  this  case  the  glass 
should  be  thoroughly  washed  and  dried,  as  mentioned  at  page 
1385,  and  afterwards  sifted,  to  exclude  all  the  smaller  particles, 
which,  from  their  lightness,  would  have  little  effect  in  preventing 
the  aggregation  of  the  resin,  and  would  be  more  troublesome  to 
separate  from  the  varnish. 

When  heat  is  employed  in  making  spirit  varnishes,  the 
lowest  temperature  should  be  used  that  will  suffice  to  dissolve 
the  resins,  as  otherwise  there  is  risk  of  losing  a  considerable 
portion  of  the  alcohol  by  evaporation,  thereby  reducing  the 
strength  of  the  spirit ;  the  varnish  is  also  liable  to  be  made  of  a 
darker  colour  by  excess  of  heat,  and  those  containing  shell  lac 

I  are  less  clear  and  hard  when  made  with  heat  than  when  made 
quite  cold,  as  the  heated  spirit  dissolves  the  greater  portion  of 
the  wax  contained  in  the  shell  lac,  and  which  becomes  dissemi- 

Inated  throughout  the  mass ;  but  when  the  solution  is  made 
without  heat,  the  principal  portion  of  the  wax  and  other  impuri- 
ties remain  undissolved  at  the  bottom. 

In  making  large  quantities  of  spirit  varnish  with  heat,  a  still 
and  worm  are  sometimes  employed,  in  order  to  prevent  loss  by 
evaporation  ;  the  still  is  heated  by  a  steam  or  water-bath,  and 
the  resins  and  solvent  are  agitated  by  a  stirring-rod  passing 
through  a  stuffing-box  in  the  head  of  the  still.  Quantities  of 
two  or  three  gallons  are  generally  made  in  a  tin  can,  which  is 
dipped  at  frequent  intervals  into  hot  water,  and  agitated  between 
every  dip  by  rolling  ;  but  in  this  case  it  is  necessary  to  loosen 
the  cork  every  time  it  is  immersed  in  the  hot  water,  in  order  to 
allow  the  vapour  of  the  spirit  to  escape,  or  otherwise  the  cork 
would  be  driven  out  with  great  force,  and  some  of  the  spirit 


13,91  WHITE    HARD   SPIRIT    VARNISHES. 

might  be  thrown  on  the  fire  with  risk  of  serious  accident.  Glass 
bottles,  although  convenient  from  their  transparency,  should 
never  be  employed  for  making  varnish  with  heat,  as  they  are 
liable  to  break  from  the  alternations  of  temperature.  They  are, 
however,  often  used  for  making  small  quantities,  and  in  this  case 
the  safer  practice  is  to  heat  the  water  only  in  a  moderate  degree, 
and  to  allow  of  the  continuous  escape  of  the  vapour  through  a 
small  notch  cut  lengthways  in  the  cork,  and  which  may  be  closed 
by  the  thumb  when  the  bottle  is  shaken.  There  is,  however,  always 
some  little  risk  of  accident  in  making  spirit  varnishes  near  an 
open  fire,  when  much  heat  is  employed ;  and  a  water  or  sand- 
bath,  placed  on  the  top  of  a  stove  so  as  to  be  heated  only  in  a 
moderate  degree,  will  be  generally  found  to  afford  sufficient 
warmth,  and  is,  perhaps,  the  most  safe  and  convenient  arrange- 
ment for  occasional  purposes. 

Shell  lac  never  requires  more  than  a  very  moderate  warmth 
to  dissolve  it,  and  the  solution  is  frequently  made  in  stone 
bottles  placed  near  a  fire  and  shaken  occasionally.  When  it  is 
required  to  be  very  clear  as  for  metal  lacker,  it  should  be  passed 
through  filtering  paper,  before  it  is  bottled. 

It  need  scarcely  be  observed,  that  all  the  utensils  employed  in 
making  spirit  varnishes  should  be  perfectly  clean  and  dry,  as  the 
least  moisture  or  even  a  damp  atmosphere  is  liable  to  deteriorate 
the  quality  of  the  varnish. 

Best  white  hard  spirit  varnish  to  bear  polishing  is  made  by 
adding  2  Ibs.  of  the  best  picked  gum  sandarac  to  1  gallon  of 
spirit  of  wine,  they  are  then  shaken  up  without  intermission  for 
about  four  hours,  or  until  the  gum  is  quite  dissolved,  18  ounces 
of  Venice  turpentine  is  then  moderately  warmed,  in  a  water 
bath,  to  make  it  fluid,  and  poured  into  the  varnish  to  give  it  a 
body.  The  whole  is  then  well  agitated  for  about  one  hour,  and 
afterwards  strained  and  put  into  bottles,  which  should  be  kept 
well  corked  to  prevent  the  evaporation  of  the  spirit.  After 
standing  about  a  week  the  varnish  is  fit  for  use.  This  varnish 
may  be  made  sufficiently  pale  to  be  used  on  white  work  when 
the  clearest  and  palest  pieces  of  the  gum  are  carefully  select 
When  the  work  does  not  require  to  be  polished  the  proporti 
of  Venice  turpentine  may  be  reduced  one  half. 

White  hard  varnish  is  also  made  with  3£  Ibs.  of  gum  sanda: 
to  1  gallon  of  spirit  of  wine,  and  when  they  are  dissolved 


BROWN  HARD  SPIRIT  VARNISHES FRENCH  POLISH,    ETC.        1392 


pint  of  pale  turpentine  varnish  is  added  and  the  whole  are  well 
shaken  until  thoroughly  mixed.  Another  white  hard  varnish  is 
made  with  2  Ibs.  of  gum  sandarac,  1  Ib.  of  gum  mastic,  and 
1  gallon  of  spirit  of  wine. 

White  spirit  varnish  for  violins  is  made  with  2  Ibs.  of  mastic 
to  1  gallon  of  spirit  of  wine,  and  1  pint  of  turpentine  varnish. 
This  may  be  made  either  in  the  same  manner  as  the  white  hard 
varnish,  or  the  ingredients  may  all  be  mixed  together  in  a  tin  can, 
placed  in  a  warm  situation  near  a  fire  and  shaken  occasionally 
until  dissolved. 

Brown  hard  spirit  varnish  is  made  in  the  same  manner  as 
white  hard  varnish,  but  shell  lac  is  generally  used  instead  of 
sandarac.  Thus  a  very  excellent  brown  hard  spirit  varnish  that 
will  bear  polishing  is  made  with  2  Ibs.  of  shell  lac  to  1  gallon  of 
spirit  of  wine,  and  after  they  are  amalgamated,  18  ounces  of 
Venice  turpentine  is  warmed  and  added  exactly  as  described 
for  the  best  white  hard  varnish.  Another  very  good  brown 
hard  spirit  varnish  consists  of  2  Ibs.  shell  lac,  1  Ib.  of  sandarac, 
and  2  ounces  of  mastic,  dissolved  in  1  gallon  of  spirits  of  wine. 
A  lighter  coloured  varnish  is  made  with  2  Ibs.  of  sandarac,  lib. 
of  shell  lac,  and  1  gallon  of  spirit.  After  the  resins  are  dissolved 

1  pint  of  turpentine  varnish  is  added  and  the  whole  is  well  mixed 
by  agitation. 

Hardwood  lacker  is  made  like  the  brown  hard  varnish  with 

2  Ibs.  of  shell  lac  to  1   gallon  of  spirit  of  wine,  but  without 
turpentine.     Another  hardwood  lacker  is  made  with  1    Ib.  of 
seed  lac  and  1  Ib.  of  white  rosin  dissolved  in  1  gallon  of  spirits 
of  wine. 

French  polish  is  made  in  a  great  variety  of  ways,  but  the 
simplest,  and  probably  the  best,  consists  of  H  Ibs  of  shell  lac 
dissolved  in  1  gallon  of  spirits  of  wine  without  heat.  Copal, 
sandarac,  mastic,  and  gum  arabic,  are  frequently  used  in  making 
French  polish,  partly  with  the  view  of  making  the  polish  of  a 
lighter  colour,  and  partly  to  please  the  fancy  of  the  polisher, 
and  the  proportions  of  the  different  gums  are  varied  almost 
finitely,  but  with  little  advantage.  A  polish  that  is  by  some 
nsidered  to  be  very  good  is  made  with  1 2  ounces  of  shell  lac, 
ounces  of  gum  arabic,  and  3  ounces  of  copal  to  1  gallon  of 
irits  of  wine.  When  a  dark  coloured  polish  is  required,  £  Ib. 
of  Benzoin  is  sometimes  added  to  1  Ib.  of  shell  lac  dissolved  in 


1393 


FRENCH    POLISH — BLEACHING    LAC    VARNISH. 


1  gallon  of  spirits,  or  4  ounces  of  guaiacum  are  added  to  l£  Ibs. 
of  shell  lac  ;  at  other  times  the  polish  is  coloured  to  the  required 
tint  with  dragon's  blood. 

The  shell  lac  alone  makes  the  hardest  and  most  durable 
polish,  and  it  is  a  frequent  practice  to  make  the  polish  rather 
thicker  in  the  first  instance  than  it  is  required  for  use,  as  it  may 
be  readily  thinned  by  the  addition  of  spirit.  But  if  it  should  be 
made  too  thin  originally,  it  would  require  to  be  thickened  by 
dissolving  a  further  portion  of  shell  lac.  With  the  view  of 
avoiding  any  risk  of  the  polish  being  made  too  thin  in  the  first 
instance,  the  proportion  of  shell  lac  is  frequently  made  2  Ibs.  to 
the  gallon  of  spirit,  Other  resins  are  sometimes  added,  with 
the  view  of  making  the  polish  tougher.  Thus  sometimes  the 
polish  is  made  with  l£  Ibs.  of  shell  lac,  4  ounces  of  seed  lac,  4 
ounces  of  sandarac,  and  2  ounces  of  mastic  to  the  gallon  of 
spirit ;  at  other  times  the  proportions  are  2  Ibs.  of  shell  lac  and 
4  ounces  of  Thus  to  the  gallon  of  spirit. 

When  a  lighter  coloured  lac  varnish,  or  polish,  is  required 
than  can  be  made  with  the  palest  ordinary  shell  lac,  the 
bleached  lac,  sold  under  the  name  of  white  lac,  may  be  employed 
with  advantage.  The  varnish  made  with  the  white  lac  is  at  first 
almost  colourless,  but  becomes  darker  by  exposure  to  the  light. 

Various  modes  have  been  adopted  for  bleaching  lac  varnish. 
In  1827  the  Society  of  Arts  rewarded  Mr.  G.  Field  and  Mr.  H. 
Luning  for  their  methods  of  effecting  this  object,  which  are 
described  in  Vol.  XLV.  of  the  Society's  Transactions.  Mr. 
Field's  process  is  as  follows  :  "  Six  ounces  of  shell  lac,  coarsely 
pounded,  are  to  be  dissolved  by  gentle  heat  in  a  pint  of  spirits  of 
wine ;  to  this  is  to  be  added  a  bleaching  liquor,  made  by  dis- 
solving purified  carbonate  of  potash  in  water,  and  then  impreg- 
nating it  with  chlorine  gas  till  the  silica  precipitates,  and  the 
solution  becomes  slightly  coloured.  Of  the  above  bleaching 
liquor  add  one  or  two  ounces  to  the  spirituous  solution  of  lac, 
and  stir  the  whole  well  together ;  effervescence  takes  place,  and 
when  this  ceases,  add  more  of  the  bleaching  liquor,  and  thus 
proceed  till  the  colour  of  the  mixture  has  become  pale.  A 
second  bleaching  liquid  is  now  to  be  added,  made  by  diluting 
muriatic  acid  with  thrice  its  weight  of  water,  and  dropping  into 
it  pulverized  red  lead,  till  the  last  added  portions  do  not  become 
white.  Of  this  acid  bleaching  liquor,  small  quantities  at  a  time 


BLEACHING    LAC    VARNISH.  1394 

are  to  be  added  to  the  half-bleached  lac  solution,  allowing  the 
effervescence,  which  takes  place  on  each  addition,  to  cease  before 
a  fresh  portion  is  poured  in.  This  is  to  be  continued  till  the 
lac,  now  white,  separates  from  the  liquor.  The  supernatant 
fluid  is  now  to  be  poured  away,  and  the  lac  is  to  be  well  washed 
in  repeated  waters,  and  finally  wrung  as  dry  as  possible  in  a 
cloth." 

Mr.  Luning's  process  is  as  follows :  "  Dissolve  5  ounces  of 
shell  lac  in  a  quart  of  rectified  spirits  of  wine ;  boil  for  a  few 
minutes  with  10  ounces  of  well- burnt  and  recently-heated  animal 
charcoal,  when  a  small  quantity  of  the  solution  should  be  drawn 
off  and  filtered  ;  if  not  colourless,  a  little  more  charcoal  must  be 
added.  When  all  colour  is  removed  press  the  liquor  through 
silk,  as  linen  absorbs  more  varnish,  and  afterwards  filter  it 
through  fine  blotting  paper." 

Dr.  Hare's  process,  published  in  the  "  Franklin  Journal,"  and 
reprinted  in  the  ''Technological  Repository,"  Vol.  I,  1827,  is  as 
follows :  "  Dissolve  in  an  iron  kettle  one  part  of  pearlash  in 
about  eight  parts  of  water,  add  one  part  of  shell  or  seed  lac,  and 
heat  the  whole  to  ebullition.  When  the  lac  is  dissolved  cool 
the  solution,  and  impregnate  it  with  chlorine  gas  till  the  lac  is 
all  precipitated.  The  precipitate  is  white,  but  the  colour  deepens 
by  washing  and  consolidation  ;  dissolved  in  alcohol,  lac  bleached 
by  the  process  above  mentioned  yields  a  varnish  which  is  as  free 
from  colour  as  any  copal  varnish." 

A  nearly  colourless  varnish  may  also  be  made  by  dissolving 
lac  as  in  Dr.  Hare's  process ;  bleaching  it  with  a  filtered 
)lution  of  chloride  of  lime,  and  afterwards  dissolving  the  lime 
rorn  the  precipitate,  by  the  addition  of  muriatic  acid.  The  pre- 
cipitate is  then  to  be  well  washed  in  several  waters,  dried,  and 
dissolved  in  alcohol,  which  takes  up  the  more  soluble  portion, 
forming  a  very  pale  but  rather  thin  varnish,  to  which  a  small 
quantity  of  mastic  may  be  added. 

Attempts  are  frequently  made  to  combine  copal  with  all  the 
spirit  varnishes,  in  order  to  give  them  greater  toughness  and 
durability,  and  although  copal  cannot  be  entirely  dissolved  even 
in  pure  alcohol,  still  a  moderate  portion  will  be  taken  up  by 
strong  spirit  of  wine  when  a  temperature  of  about  120°  is 
employed  with  frequent  agitation  of  the  varnish.  In  this 
manner  a  light  coloured  varnish  may  be  made  with  |  Ib.  of  shell 

VOL.  III.  B  B 


1395  LACKER    FOR    BRASS. 


lac,  I  Ib.  of  copal  to  1  gallon  of  spirits  of  wine  containing  about 
95  per  cent,  of  alcohol.  The  copal  should  be  powdered  quite 
fine,  and  may  either  be  added  to  the  shell  lac  and  spirit  at  the 
commencement,  in  which  case  the  shell  lac  should  also  be 
powdered,  or  the  shell  lac  may  be  first  dissolved,  and  the 
powdered  copal  added ;  but  in  either  case  it  is  only  the  more 
soluble  portion  of  the  copal  that  is  taken  up,  and  the  remainder 
settles  to  the  bottom  in  a  viscid  mass,  from  which  the  varnish 
may  be  decanted  and  strained  for  use.  Copal  may  be  added  in 
the  same  manner  to  the  white  hard  varnishes,  and  it  is  some- 
times recommended  to  fuse  the  copal  and  drop  it  into  water 
before  attempting  to  dissolve  it  in  spirit,  but  the  advantage  of 
adding  copal  to  spirit  varnishes  is  very  questionable. 

Lacker  for  brass  like  French  polish  is  made  in  a  great  variety 
of  ways,  and  as  in  French  polish  the  simplest  and  best  pale 
lacker  for  works  that  do  not  require  to  be  coloured,  consists 
of  shell  lac  and  spirits  of  wine  only,  in  the  proportions  of  about 
i  Ib.  of  the  best  pale  shell  lac  to  1  gallon  of  spirit.  Lacker  is 
required  to  be  as  clear  and  bright  as  possible ;  it  is  therefore 
always  made  without  heat  by  continuous  agitation  for  five  or 
six  hours.  The  lacker  is  then  allowed  to  stand  until  the  thicker 
portions  are  precipitated,  when  the  clear  lacker  is  poured  off, 
and  if  it  should  not  be  sufficiently  clear,  it  is  afterwards  filtered 
through  paper  into  a  bottle,  which  should  be  kept  closely  corked 
and  out  of  the  influence  of  light  which  would  darken  the  colour 
of  the  lacker.  This  may  however  be  easily  prevented  by  pasting 
paper  round  the  bottle. 

Lackers  are  frequently  required  to  be  coloured  either  of 
yellow  or  red  tints.  For  yellow  tints  turmeric,  cape  aloes, 
saffron  or  gamboge  are  employed,  and  for  red  tints  annotto  and 
dragon's  blood  are  used  ;  the  proportions  being  varied  accord- 
ing to  the  colour  required.  Thus,  for  a  pale  yellow,  about 
1  ounce  of  gamboge  and  2  ounces  of  cape  aloes  are  powdered 
and  mixed  with  1  Ib.  of  shell  lac.  For  a  full  yellow,  i  Ib.  of 
turmeric  and  2  ounces  of  gamboge,  and  for  a  red  lacker,  £  Ib.  of 
dragon's  blood  and  1  Ib.  of  annotto.  The  colour  is  also  modified 
by  that  of  the  lac  employed,  the  best  pale  or  orange  shell  lac 
being  used  for  light  coloured  lackers,  and  darker  coloured  shell 
lac,  or  seed  lac,  is  used  for  the  darker  tints.  For  pale  lackers 
sandarac  is  sometimes  used  with  the  shell  lac.  Thus  a  pale 


LACKER    FOR    BRASS MASTIC    VARNISH.  1396 

gold-coloured  lacker  is  made  with  8  ounces  of  shell  lac,  2  ounces 
of  sandarac,  8  ounces  of  turmeric,  2  ounces  of  annotto,  and  J 
ounce  of  dragon's  blood  to  1  gallon  of  spirits  of  wine. 

The  most  convenient  method,  however,  of  colouring  lackers, 
is  to  make  a  saturated  solution  in  spirits  of  wine  of  each  of  the 
colouring  matters,  and  to  add  the  solutions  in  different  propor- 
tion to  the  pale  lacker  according  to  the  tint  required,  but  the 
whole  of  the  colouring  matters  are  not  generally  used  by  the 
same  makers,  and  solutions  of  turmeric,  gamboge,  and  dragon's 
blood,  afford  sufficient  choice  for  ordinary  purposes.  The  tur- 
meric gives  a  greenish  yellow  tint,  and  with  the  addition  of  a 
little  gamboge,  is  the  colouring  matter  employed  in  making  the 
so  called  green  lacker  used  for  bronzed  works,  as  noticed  at 
page  1413. 

Another  mode  of  making  lacker  is  followed  by  Mr.  A.  Ross  : 
4  ounces  of  shell  lac  and  J  ounce  of  gamboge  are  dissolved  by 
agitation  without  heat  in  24  ounces  of  pure  pyro-acetic  ether. 
The  solution  is  allowed  to  stand  until  the  gummy  matters  not 
taken  up  by  the  spirit  subside,  the  clear  liquor  is  then  decanted, 
and  when  required  for  use  is  mixed  with  eight  times  its  quantity 
of  spirits  of  wine.  In  this  case,  the  pyro-acetic  ether  is  em- 
ployed for  dissolving  the  shell  lac  in  order  to  prevent  any  but 
the  purely  resinous  portions  being  taken  up,  which  is  almost 
certain  to  occur  with  ordinary  spirits  of  wine,  owing  to  the 
resence  of  water ;  but  if  the  lacker  were  made  entirely  with 

•o-acetic  ether,  the  latter  would  evaporate  too  rapidly  to 
w  time  for  the  lacker  to  be  equally  applied. 

Mastic  varnish  for  paintings,  and  similar  purposes,  is  some- 
es  made  in  small  quantities  with  spirits  of  wine ;  but  more 

merally  oil  of  turpentine  is  employed  as  the  solvent,  the 
•roportion  being  about  3  Ibs.  of  mastic  to  the  gallon  of  tur- 
pentine. For  the  best  varnish  the  mastic  is  carefully  picked 
and  dissolved  by  agitation  without  heat,  exactly  as  for  the  best 
white  hard  varnish,  and  after  the  mastic  varnish  has  been 
ined  it  is  poured  into  a  bottle,  which  is  loosely  corked  and 

posed  to  the  sun  and  air  for  a  few  weeks ;  this  causes  a  pre- 
cipitation from  which  the  clear  varnish  may  be  poured  off  for 
use,  but  the  longer  the  varnish  is  kept  the  better  it  becomes. 

Mastic  varnish  works  very  freely,  but  is  liable  to  chill,  and 
the  surface  frequently  remains  tacky  for  some  time  after  the 

B  B2 


wmte 
exDos< 


1397  TURPENTINE    AND    CRYSTAL    VARNISHES. 

varnish  is  applied.  To  prevent  the  latter  evil,  it  is  recom- 
mended before  dissolving  the  mastic  to  bruise  it  slightly  with  a 
muller,  and  pick  out  all  the  pieces  that  are  too  soft  to  break 
readily,  and  which  may  be  used  for  common  varnish.  To 
prevent  the  chilling,  which  arises  from  the  presence  of  moisture, 
Mr.  W.  Neil  recommends  a  quart  of  river  sand  to  be  boiled 
with  two  ounces  of  pearlash  ;  the  sand  is  afterwards  to  be 
washed  three  or  four  times  with  hot  water,  and  strained  each 
time.  The  sand  is  afterwards  to  be  dried  in  an  oven,  and  when 
it  is  of  .a  good  heat,  half  a  pint  of  the  hot  sand  is  to  be  poured 
into  each  gallon  of  varnish,  and  shaken  well  for  five  minutes,  it  is 
then  allowed  to  settle,  and  carries  down  the  moisture  of  the  gum 
and  turpentine. 

In  making  common  varnish,  heat  is  generally  employed  to 
dissolve  the  mastic,  and  about  one  pint  of  turpentine  varnish  is 
added  to  every  gallon  of  varnish. 

Turpentine  varnish  is  made  with  4  Ibs.  of  common  resin  dis- 
solved in  1  gallon  of  oil  of  turpentine,  it  requires  no  other 
preparation  than  sufficient  warmth  to  dissolve  the  resin ;  some- 
times the  resin  and  turpentine  are  mixed  together  in  a  stone 
or  tin  bottle,  which  is  placed  near  the  fire,  or  in  a  sand  bath 
over  a  stove,  and  shaken  occasionally,  but  varnish  makers 
generally  mix  the  resin  and  turpentine  in  the  gum-pot,  and 
employ  sufficient  heat  to  fuse  the  resin.  This  is  a  more 
expeditious  practice,  but  is  attended  with  some  danger  of  fire. 
When  a  very  pale  turpentine  varnish  is  required,  bleached  resin 
is  used,  and  care  is  taken  not  to  employ  more  heat  than  is 
necessary  in  making  the  varnish.  Turpentine  varnish  is  prin- 
cipally used  for  in-door  painted  works  and  common  painted 
furniture,  and  toys.  It  is  also  frequently  added  to  other 
varnishes  to  give  them  greater  body,  hardness,  and  brilliancy. 

Crystal  varnish  is  a  name  frequently  given  to  very  pale 
varnishes  employed  for  paper  works,  such  as  maps,  coloured 
prints,  and  drawings.  A  very  good  crystal  varnish  is  made 
with  2  Ibs.  of  mastic  and  2  Ibs.  of  damar,  dissolved  without  heat 
in  1  gallon  of  turpentine.  Another  good,  but  more  expensive, 
crystal  varnish  is  made  with  equal  quantities  of  Canada  balsam 
and  oil  of  turpentine.  In  making  this  varnish  it  is  only  necessary 
to  warm  the  Canada  balsam  until  it  is  quite  fluid,  then  add  the 
turpentine  and  shake  the  mixture  for  a  few  minutes  until  the 


PAPER,    WATER,    AND    SEALING-WAX    VARNISHES.  1398 

two  are  thoroughly  incorporated.  The  varnish  may  then  be 
placed  in  a  moderately  warm  situation  for  a  few  hours,  and 
will  be  ready  for  use  on  the  following  day.  These  crystal 
varnishes  are  both  nearly  colourless,  flow  freely,  and  are  mode- 
rately flexible,  so  as  to  bear  bending,  or  rolling,  and  either  of 
them  may  be  employed  to  make  a  tracing  paper  of  middling 
quality,  by  applying  a  thin  coat  of  varnish  on  one  or  both  sides 
of  any  thin  transparent  paper,  such  as  good  tissue  or  foreign 
post  paper. 

Paper  varnish,  for  paper  hangings  and  similar  purposes,  is 
made  with  4  Ibs.  of  damar  to  1  gallon  of  turpentine.  The  damar 
dissolves  very  readily  in  the  turpentine,  either  with  moderate 
agitation  or  a  very  gentle  heat.  Sometimes  white  or  bleached 
resin  is  used  instead  of  the  damar,  or  the  two  are  combined. 

Water  varnish. — All  the  varieties  of  lac  may  be  dissolved  in 
nearly  boiling  water  by  the  addition  of  ammonia,  borax,  potash, 
or  soda,  but  these  alkalis  all  have  the  effect  of  rendering  the 
colour  of  the  lac  much  darker.  The  solutions  may,  however,  be 
employed  as  varnishes,  which  when  dried  will  resist  the  applica- 
tion of  water  sufficiently  well  to  bear  washing,  especially  when 
the  proportion  of  alkali  employed  is  only  just  sufficient  to  cause 
the  dissolution  of  the  lac,  and  which  is  also  desirable  in  order  to 
keep  the  varnish  as  light  coloured  as  possible. — The  least  colour 
is  given  with  diluted  water  of  ammonia,  in  the  proportions  of 
about  16  ounces  of  ordinary  water  of  ammonia  to  7  pints  of 
water  and  2  Ibs.  of  pale  shell  lac,  to  which  about  4  ounces  of 
gum  arabic  may  be  added.  Borax  is,  however,  more  generally 
used,  and  the  proportions  are  then  2  Ibs.  of  shell  lac,  6  ounces  of 
borax,  and  4  ounces  of  gum  arabic  to  1  gallon  of  water.  When 
the  varnish  is  required  to  be  as  light-coloured  as  possible,  white 
lac  is  employed. 

Dealing-wax  varnish,  for  coating  parts  of  electrical  machines 
and  similar  purposes,  is  made  by  dissolving  2J  Ibs.  of  good  red 
sealing  wax  and  1^  Ibs.  of  shell  lac  in  1  gallon  of  spirits  of  wine. 

Black  varnish  may  be  made  with  3  Ibs.  of  black  sealing-wax 
and  1  Ib.  of  shell  lac  to  the  gallon  of  spirit,  or  fine  lamp  black 
may  be  mixed  with  brown  hard  varnish  or  lacker,  according  to 
the  thickness  required  in  the  varnish.  The  interior  of  telescope 
tubes  are  frequently  blackened  with  a  dull  varnish  of  this  kind, 
made  by  mixing  lamp  black  with  rather  thick  brass  lacker,  as 


1399  APPLICATION    OF    SPIRIT    VARNISHES. 

little  of  the  lamp  black  being  employed  as  will  serve  to  deaden 
the  bright  colour  of  the  lacker.  Mathematical  instruments  are 
sometimes  blackened  with  a  similar  thin  varnish,  and  the  surface 
is  afterwards  brightened  with  one  or  two  coats  of  lacker  applied 
as  usual.  Ordinary  lamp  black,  however,  generally  contains 
greasy  impurities  and  moisture  which  render  it  unfit  for  varnish 
purposes,  and  therefore  the  best  kind  should  be  employed,  or 
the  lamp  black  should  be  purified  by  ramming  it  hard  into  a 
close  vessel,  and  afterwards  subjecting  it  to  a  red  heat.  In  the 
workshop,  when  small  quantities  of  lamp  black  are  required,  it  is 
frequently  made  for  the  occasion,  by  placing  a  piece  of  sheet 
metal  over  the  flame  of  an  oil  lamp.  A  black  varnish,  sometimes 
used  for  metal  works,  is  made  by  fusing  3  Ibs.  of  Egyptian 
asphaltum,  and  when  well  dissolved,  \  Ib.  of  shell  lac  and  1 
gallon  of  turpentine  are  added. 


SECTION    II. APPLICATION    OF    VARNISHES. 

IN  varnishing  flat  surfaces  the  varnishes  are  all  applied  like 
paint,  with  brushes  that  should  be  soft,  and  perfectly  clean. 
For  spirit  varnishes,  camel's  hair  pencils  and  brushes  are  used, 
the  sizes  of  which  vary  from  one  quarter  to  three-quarters  of  an 
inch  diameter,  according  to  the  size  of  the  work.  When  the 
surfaces  are  very  large,  flat  camel  hair  brushes  are  used ;  but 
from  their  comparative  thinness,  they  scarcely  contain  a  sufficient 
quantity  of  varnish  to  preserve  the  brush  uniformly  charged  in 
passing  over  a  large  surface.  Turpentine  and  oil  varnishes 
require  less  delicacy,  and  flat  brushes,  made  of  fine  soft  bristles, 
are  generally  used,  or  sometimes  ordinary  painting  brushes  are 
employed  ;  but  they  are  rather  harsh,  and,  owing  to  the  adhesion 
of  the  varnish,  the  hairs  are  apt  to  be  loosened,  and  come  out. 

The  varnishes  should  all  be  uniformly  applied,  in  very  thin 
coats,  very  sparingly  upon  the  edges  and  angles,  where  the 
varnish  is  liable  to  accumulate ;  and  a  sufficient  interval  of  time 
should  be  allowed  between  every  coat  for  the  perfect  evaporation 
of  the  solvent,  whether  alchohol,  turpentine,  or  oil.  The  time 
required  for  this  depends  partly  on  the  kind  of  varnish  employed, 
and  partly  on  the  state  of  the  atmosphere  ;  but,  under  ordinary 
circumstances,  spirit  varnishes  generally  require  from  two  to  three 
hours  between  every  coat.  Turpentine  varnishes  mostly  require 


NECESSITY    FOR    DRY    ATMOSPHERE.  1400 

six  or  eight  hours,  and  oil  varnishes  still  longer, — sometimes  as 
much  as  twenty -four  hours.  But  whatever  time  may  be  required, 
the  second  layer  should  never  be  added  until  the  first  is  perma- 
nently hard;  as  when  one  layer  is  defended  from  the  air  by  a 
second,  its  drying  is  almost  entirely  stopped,  and  it  remains  soft 
and  adhesive.  Every  precaution  should  also  be  taken  to  prevent 
any  dust,  or  loose  hairs  from  the  brush,  becoming  accidentally 
attached  to  the  varnish  ;  should  this  occur,  they  should  be  imme- 
diately removed  before  the  varnish  drys,  or  otherwise  they  will 
require  to  be  carefully  picked  out  with  the  point  of  a  pen-knife, 
and  the  surface  of  the  varnish  levelled  with  fine  glass-paper, 
prior  to  the  application  of  the  next  coat. 

In  using  spirit  varnishes  it  is  at  all  times  of  the  first  impor- 
tance that  particular  attention  should  be  bestowed  upon  carrying 
on  the  varnishing  in  a  dry  atmosphere  ;  as  all  solutions  of  resins 
in  alcohol  are  precipitated  by  the  addition  of  water,  not  only  as 
visible  moisture,  but  even  as  vapour,  which  is  at  all  times 
deposited  by  the  atmosphere  at  a  reduced  temperature,  in  the 
form  of  invisible  dew,  and  in  this  state  it  precipitates  the  resin 
in  the  thin  coat  of  varnish,  and  gives  the  surface  a  milky, 
opake,  or  clouded  appearance,  when  the  varnish  is  said  to  be 
chilled ;  but  this  effect  is  frequently  produced  even  on  a  warm 
and  apparently  fine  summer  day,  when  the  atmosphere  happens 
to  be  more  than  usually  charged  with  moisture.  This  is  a 
frequent  stumbling  block  in  varnishing,  and  is  only  to  be 
obviated,  by  carrying  on  the  process  in  a  room  sufficiently  warmed 
to  keep  the  moisture  suspended  in  the  air,  until  the  solvent  has 
entirely  evaporated,  and  left  the  resin  as  a  thin  glassy  coat  but 
little  altered,  in  a  chemical  point  of  view,  from  its  primary  state 
of  fragment,  flake,  or  grain,  and  entirely  unacted  upon  by  water, 
upon  which  circumstance  the  brilliancy  and  defensive  value  of 
the  varnish  depends. 

Not  only  should  the  room  be  sufficiently  heated,  but  all 
currents  of  cold  air  must  be  avoided,  as  cold  draughts  from  the 
interstices  of  the  door  or  window,  if  suffered  to  pass  over  the 
recently  varnished  surface,  are  quite  sufficient  to  dull  the  varnish 
wherever  they  extend.  When  the  varnish  has  been  chilled,  the 
brilliancy  and  clearness  may  frequently  be  restored  by  giving 
the  chilled  surface  another  thin  coat  of  varnish,  taking  care  to 
avoid  the  causes  of  the  former  failure,  and  immediately  holding 


1401  APPLICATION    OF    SPIRIT    VARNISHES. 


the  varnished  surface  at  a  moderate  distance  from  a  fire,  so  as 
to  warm  it  sufficiently  to  partially  redissolve  the  chilled  coat ; 
but  care  is  necessary  to  avoid  heating  the  varnish  so  much  as  to 
raise  blisters,  which  would  spoil  the  surface,  and  no  remedy 
would  remain  but  to  rub  off  the  entire  coat  of  varnish  with 
glass-paper,  and  recommence  the  process. 

The  temperature  generally  preferred  for  the  varnishing  room, 
is  about  72°  F.  ;  but  a  few  degrees  more  or  less  are  not  very 
important.  The  works  to  be  varnished  should  be  kept  in  the 
room  for  a  few  hours  before  varnishing,  in  order  that  they  may 
acquire  the  same  temperature  as  the  atmosphere,  and  the  sur- 
faces should  be  smoothed  with  fine  glass-paper,  to  remove  all 
traces  of  moisture  or  grease,  and  if  it  should  be  necessary  to  stop 
any  minute  holes  in  the  wood  before  varnishing,  it  should  be 
done  with  some  of  the  gums,  or  with  wax,  or  at  all  events, 
nothing  containing  oil  or  grease  should  be  employed. 

An  ordinary  preserve-jar  is  frequently  used  for  containing 
the  varnish,  and  is  sufficiently  suitable ;  but  it  is  desirable  to 
have  a  wire  or  string  fixed  across  the  top,  for  reducing  the 
quantity  taken  up  by  the  brush,  which  is  wiped  against  the  wire 
every  time  that  it  is  dipped  into  the  varnish.  The  quantity  of 
varnish  poured  into  the  jar  should  "be  sufficient  to  nearly  cover 
the  hairs  of  the  brush,  in  order  to  keep  it  soft.  Too  small  a 
quantity  of  varnish  is  liable  to  thicken  rapidly  by  evaporation, 
which  should  at  all  times  be  prevented,  as  far  as  possible,  by 
keeping  the  vessel  closely  covered  when  not  actually  in  use. 
Should  the  varnish,  however,  become  too  thick,  it  may  be 
readily  thinned  by  the  addition  of  spirits  of  wine,  and  for  good 
work  it  is  more  desirable  to  apply  an  increased  number  of  thin 
coats  than  to  use  the  varnish  when  too  thick,  as  the  surface  is 
then  almost  certain  to  appear  irregular,  and  full  of  lines. 

In  applying  spirit  varnish,  some  little  tact  and  expedition  are 
necessary,  in  order  to  spread  the  varnish  uniformly  over  the 
surface  before  it  becomes  too  much  thickened  by  evaporation, 
or  it  will  exhibit  a  very  irregular  surface  when  finished.  If  the 
surface  does  not  exceed  a  few  inches  square,  no  material  difficulty 
is  experienced,  as  the  whole  may  be  brushed  over  two  or  three 
times  before  the  varnish  becomes  too  thick ;  but  surfaces  con- 
taining two  or  three  square  feet  present  much  greater  difficulty, 
as  it  is  "necessary  that  the  varnish  should  be  sufficiently  worked 


APPLICATION    OF    SPIRIT    VARNISHES.  1402 


with  the  brush,  to  exclude  all  minute  air-bubbles,  which  would 
spoil  the  appearance  of  the  work,  and  can  seldom  be  entirely 
removed  until  just  before  the  varnish  is  becoming  too  thick  to 
flow  or  spread  uniformly  after  the  brush  has  passed  over  it. 

In  first  placing  the  brush  on  the  surface,  it  should  be  applied, 
not  close  to  the  edge,  which  would  be  liable  to  give  too  thick  a 
coat  at  that  part,  but  at  a  little  distance  from  the  edge,  and  the 
strokes  of  the  brush  should  be  directed  towards  the  ends  alter- 
nately, with  steady  rapid  strokes  and  only  very  moderate 
pressure.  If  the  surface  is  small,  the  whole  may  be  passed  over 
at  the  one  operation,  and  then  the  brush  may  be  returned  to 
the  edge  at  which  it  was  first  commenced,  and  it  may  be  passed 
over  the  surface  in  the  same  manner  a  second  or  third  time,  to 
distribute  the  varnish  uniformly,  and  work  out  the  air-bubbles. 
Sometimes,  in  small  surfaces,  the  second  series  of  strokes  is  made 
at  right  angles  with  the  first,  in  order  to  distribute  the  varnish 
more  equally,  and  the  third  is  laid  on  in  the  same  direction  as 
the  first;  but  unless  this  is  done  expeditiously  and  equally,  it 
leaves  cross  lines,  which  injure  the  appearance  of  the  work. 

Large  surfaces  are  more  difficult,  as  the  varnish  thickens  too 
rapidly  to  allow  of  the  entire  surface  being  covered  at  one  opera- 
tion ;  they  must  therefore  either  be  worked  gradually  from  the 
one  edge  to  the  other,  as  in  laying  a  tint  of  water-colour,  or  the 
varnish  must  be  applied  upon  separate  portions  successively ;  but 
it  is  rather  difficult  to  join  the  portions  without  leaving  irregular 
marks.  It  may,  however,  be  successfully  executed  by  thinning 
off  the  edges  of  the  first  pieces,  and  allowing  the  adjoining  por- 
tion to  overlap  also  by  thinning  off  the  edge  with  light  strokes 
of  the  brush,  made  in  the  same  direction  as  those  on  the  finished 
portion  ;  but  some  care  is  required  to  avoid  disturbing  the  former 
coat  while  it  is  still  soft  and  easily  acted  upon  by  the  fresh 
varnish.  In  the  same  manner,  in  laying  on  a  second  or  any 
subsequent  coat  of  varnish,  care  must  be  taken  not  to  continue 
the  application  of  the  brush  for  a  sufficient  length  of  time  to 
disturb  the  previous  coat,  which  is  speedily  softened  by  the  fresh 
varnish,  and  if  the  application  of  the  brush  were  continued  too 
long,  it  would  be  disturbed,  and  give  the  work  an  irregular  or 
chilled  appearance. 

Wood  and  other  porous  surfaces  absorb  a  considerable  portion 
of  the  first  coat  of  varnish,  which  sinks  in  deeper  at  the  softer 


1403  SIZING,    POLISHING,    AND    PAINTING. 

parts,  and  raises  the  grain  of  the  wood  in  a  slight  degree,  a 
second  coat  is  generally  necessary  to  fill  up  the  pores  uniformly, 
and  sometimes  even  a  third  is  required.  The  work  is  then 
rubbed  smooth  with  fine  glass-paper,  and  if  the  varnish  is  not 
to  be  polished,  two  or  three  coats  more  generally  suffice  to  finish 
the  work,  as  the  thickness  of  varnish  should  not  be  too  great,  or 
it  is  liable  to  crack  or  chip. 

With  the  view  of  economising  the  varnish,  porous  surfaces, 
such  as  wood  and  paper,  are  frequently  sized  over,  to  prevent 
the  varnish  from  sinking  into  the  surface.  For  dark  coloured 
works  thin  size,  made  from  ordinary  glue  of  good  quality,  is 
generally  used  ;  but  for  light  coloured  surfaces,  a  lighter  coloured 
size  is  used,  which  is  prepared  by  boiling  white  leather  or  parch- 
ment-cuttings in  water  for  a  few  hours,  or  until  it  forms  a  thin 
jelly-like  substance,  which  is  used  in  the  tepid  state,  and  sometimes 
solutions  of  isinglass  or  tragacanth  are  employed  in  like  manner. 
For  wood  the  choice,  except  as  to  colour,  is  nearly  immaterial,  the 
object  being  only  to  prevent  the  absorption  of  the  varnish  by  a 
very  thin  coat  of  some  substance  not  soluble  in  the  varnish ; 
but  for  paper  works  the  parchment  size  is  on  the  whole  preferable, 
as  it  is  almost  colourless,  and  tolerably  flexible.  It  is  better  in 
all  cases  to  use  two  coats  of  thin  size  than  one  of  a  thicker  con- 
sistency, as  the  size  is  more  uniformly  spread  in  two  coats,  and 
there  is  less  risk  of  any  small  spots  being  left  untouched,  which 
would  show  specks  in  the  varnish  when  completed  ;  but  no  greater 
thickness  of  size  should  be  employed  than  is  absolutely  necessary, 
or  otherwise  it  would  be  liable  to  crack  and  peel  off. 

The  method  of  polishing  the  best  varnished  works  has  been 
already  describing  in  the  catalogue  of  grinding  and  polishing 
processes,  under  the  head  VARNISHED  WORKS,  page  1101,  from 
the  practice  of  Messrs.  Erats,  from  whom  many  of  the  above  par- 
ticulars were  also  derived.  The  routine  pursued  in  the  polishing 
of  japanned  works  is  briefly  mentioned  at  page  1069,  and  similar 
methods  are  used  with  trifling  variations,  for  polishing  all  other 
varnished  works. 

Ornamental  painting  on  varnished  works  is  executed  as  men- 
tioned in  page  1101,  after  the  general  surface  has  received  a 
ground  of  about  six  coats  of  varnish,  and  been  rubbed  smooth 
and  level.  The  colours  employed  should  be  of  the  best  quality, 
ground  as  fine  as  possible  with  turpentine,  and  mixed  to  the  * 


VARNISHED    WORKS JAPANNING.  1404 

proper  consistence  with  the  same  varnish  that  is  employed  for 
the  general  surface.  So  far  as  convenient  the  transparent 
colours  are  to  be  preferred,  and  those  principally  used  are 
dragon's  blood,  lakes,  Prussian  blue,  chrome  yellow,  verdigris, 
white  lead,  lamp  black,  and  ivory  black.  Tincture  of  saffron  is 
also  employed  for  yellow  colours,  and  also  for  staining  the  general 
surface  of  a  yellow  tint  before  it  is  varnished ;  the  tincture  is 
made  by  macerating  half  an  ounce  of  saffron  for  two  or  three 
days  in  a  pint  of  spirits  of  wine ;  and  other  coloured  stains  are 
sometimes  prepared  and  applied  in  the  same  manner. 

Turpentine  and  oil  varnishes  are  applied  in  the  same  general 
manner  as  the  spirit  varnishes,  but  as  they  dry  slower,  more 
time  may  be  occupied  in  laying  on  the  varnish,  and  therefore 
large  surfaces  may  be  more  easily  and  uniformly  covered ;  but 
the  same  precautions  with  respect  to  the  dryness  and  warmth  of 

i  the  atmosphere  are  likewise  desirable,  when  it  is  wished  to 
produce  a  brilliant  surface. 

In  conclusion,  it  may  be  observed,  that  generally  speaking  all 
coloured  works  are  first  painted  of  the  required  tints,  and  a 
transparent  varnish  is  afterwards  laid  on  to  give  the  required 
brilliancy,  but  for  delicate  ornamental  painting  two  or  three 

!  coats  of  varnish  are  generally  laid  on  and  smoothed  down  after 
the  general  ground  has  been  painted,  in  order  to  prepare  a 
suitable  surface  for  artistic  works. 


Japanning  on  metal,  wood,  and  paper,  is  executed  in  much  the 
same  manner  as  similar  works  in  spirit  or  oil  varnishes,  except  that 
every  coat  of  colour  or  varnish  is  dried  by  placing  the  object  in  an 
oven  or  chamber  called  a  stove,  and  heated  by  flues  to  as  high  a 
temperature  as  can  safely  be  employed  without  injuring  the 
articles,  or  causing  the  varnish  to  blister  or  run.  For  ornamental 
works,  the  colours  ordinarily  employed  by  artists  are  used  ;  they 
are  ground  in  linseed  oil  or  turpentine,  and  are  afterwards 
brought  to  a  proper  consistence  for  working  by  mixing  them 
with  copal  or  anime  varnish.  The  latter  is  generally  used,  as  it 
dries  quicker,  and  is  less  expensive  than  the  copal  varnish. 

For  black  japanned  works,  the  ground  is  first  prepared  with  a 
•  coating  of  black,  made  by  mixing  drop  ivory  black  to  a  proper 
j  consistence  with  dark  coloured  anime  varnish,  as  this  gives  a 


1405  JAPANNING. 

blacker  surface  than  would  be  produced  by  the  japan  alone.  The 
object  is  then  dried  in  the  stove,  three  or  four  coats  of  japan  are 
afterwards  applied,  and  the  work  is  dried  in  the  stove  between 
every  coat.  If  the  surface  is  required  to  be  polished,  as  for  the 
best  works,  five  or  six  coats  of  japan  are  necessary  to  give 
sufficient  body  to  prevent  the  japan  being  rubbed  through  in 
the  polishing,  which  is  effected  as  noticed  briefly  in  page  1069. 

For  brown  japanned  works,  the  clear  japan  alone  is  used  as 
the  ground,  or  umber  is  mixed  with  the  japan  to  give  the  required 
tint,  and  the  work  is  afterwards  dried  in  the  oven  in  the  same 
manner  as  black  japan. 

For  coloured  works,  no  japan  is  used,  but  they  are  painted 
with  the  ordinary  painter's  colours,  ground  with  linseed  oil  or 
turpentine,  and  mixed  with  anime  varnish ;  and  the  work  is 
dried  in  the  oven  in  the  same  manner  as  the  black  japan. 

To  protect  the  colours,  and  give  brilliancy  and  durability  to 
the  surface,  the  work  is  afterwards  varnished  with  copal  or 
anime  varnish  made  without  driers.  Two  or  three  coats  of 
varnish  suffice  for  ordinary  works,  and  five  or  six  for  the  best 
works  that  are  polished.  Very  pale  varnish  is  of  course  re- 
quired for  light  colours. 

Ornamental  devices  are  painted  on  the  objects  in  the  usual 
manner,  after  the  general  colour  of  the  ground  has  been  laid  on. 
The  colours  are  dried  in  the  stove,  and  the  work  is  finally 
varnished  and  polished  just  the  same  as  plain  colours,  but  more 
carefully. 

Metal  works  require  no  other  preparation  than  cleaning  with 
turpentine,  to  free  them  from  grease  or  oil,  unless  the  latter 
should  happen  to  be  linseed  oil,  in  which  case  the  cleaning  is 
generally  dispensed  with,  and  the  articles  are  placed  in  the  stove 
and  heated  until  the  oil  is  baked  quite  hard. 

Wood  that  is  intended  to  be  used  for  the  best  japanned  works 
requires  to  be  thoroughly  well  dried  before  it  is  made  up,  or 
otherwise  it  would  be  subject  to  all  the  evils  of  shrinking,  warp- 
ing, and  splitting  when  exposed  to  the  heat  of  the  stove.  To 
avoid  these  evils,  the  wood,  after  having  been  well  seasoned  in 
the  usual  manner  by  exposure  to  the  air,  is  sawn  out  nearly  to 
the  required  forms,  and  baked  for  several  days  in  the  japanner's 
stove,  the  heat  of  which  is  gradually  increased,  and  the  wood  is 
afterwards  worked  up  into  chairs,  tables,  trays,  and  similar 


LACKERING    BRASS    WORKS.  1406 

articles,  which  are  afterwards  again  exposed  to  the  heat  of  the 
stove,  and  any  cracks  or  other  imperfections  that  may  be  thus 
rendered  apparent  are  carefully  stopped  with  putty  or  white  lead 
before  the  japanning  is  commenced. 

'Common  works  in  wood,  said  to  be  japanned,  are,  however, 
not  stoved,  but  only  painted,  either  in  varnish  or  with  common 
oil  paint,  and  afterwards  varnished  with  either  anime  or  turpen- 
tine varnish  according  to  quality.  In  the  same  manner  iron 
work  for  common  purposes  is  frequently  coated  with  black  paint, 
brunswick  black,  or  black  japan,  applied  without  heat,  and 
either  varnished  or  not,  according  to  circumstances,  but  all  these 
expedients  are  greatly  inferior  to  japanning. 


In  lackering  brass  and  similar  metals,  the  work  requires  to  be 
perfectly  cleaned  from  all  grease  or  oil,  the  presence  of  which 
would  prevent  the  adhesion  of  the  lacker,  and  usually  the  metal 
is  heated  nearly  to  the  temperature  of  boiling  water,  that  the 
spirit  may  be  rapidly  evaporated  from  the  lacker,  in  order  to 
prevent  any  risk  of  its  being  chilled  by  the  moisture  of  the 
atmosphere  being  condensed  on  the  cold  metal.  The  heat  also 
causes  the  lacker  to  attach  itself  more  firmly  to  the  metal,  and 
from  the  readiness  with  which  it  flows,  the  lacker  appears  much 
more  brilliant. 

The  heating  of  the  metal  is,  however,  not  imperative,  as  metal 
may  be  lackered  in  the  same  manner  that  spirit  varnish  is  applied 
to  wood,  but  a  dry  and  warm  atmosphere  are  then  essential,  or 
the  lackering  may  be  carried  on  in  bright  sunshine,  but  there  is 
greater  liability  of  the  adhesion  of  dust,  owing  to  the  lacker 
drying  less  rapidly,  and  on  the  whole  the  process  is  not  so 
successful  as  when  heat  is  applied. 

The  lackering  of  the  metals  should  follow  immediately  after 
the  polishing  processes,  which  have  been  already  explained  at 
page  1038,  or  if  the  lackering  must  necessarily  be  delayed,  the 
work  should  be  thoroughly  coated  with  clean  oil,  or  immersed  in 
very  pure  water,  in  order  to  retard  the  tarnishing,  but  which  will 
nevertheless  occur  in  water  after  the  lapse  of  a  few  hours  ;  with 
oil  the  polish  is  preserved  much  longer.  Works  having  orna- 
mented surfaces  from  which  the  oil  could  not  be  readily  cleaned, 


1407  LACKERING METHODS    OF    HEATING. 


are  sometimes  closely  wrapped  in  cloths  in  order  to  exclude  the 
air  as  much  as  possible,  but  the  sooner  brass  is  lackered  after 
polishing  the  more  brilliant  it  will  appear. 

The  works  polished  with  oil  are  carefully  wiped  before  they  are 
heated,  first  with  moslings,  and  afterwards  with  whitening,  applied 
either  with  a  rag  or  a  brush,  so  as  thoroughly  to  remove  all 
traces  of  grease  ;  those  polished  with  water  merely  require  to  be 
wiped  with  a  clean  cloth,  and  those  finished  by  the  dipping 
processes  are  generally  dried  in  saw-dust. 

The  work  is  heated  prior  to  lackering  in  a  variety  of  ways. 
In  manufactories  devoted  principally  to  brass  works,  there  is 
generally  a  lackering  stove,  having  a  broad  flat  top,  upon  which 
the  work  is  laid,  completely  out  of  reach  of  the  dust  or  smoke 
from  the  fire.  In  some  few  instances  a  circular  row  of  gas 
flames  is  employed,  just  as  in  gas  stoves,  for  heating  a  plate, 
which  is  supported  on  four  legs  like  a  table ;  this  method  is  very 
neat  and  appropriate. 

In  the  absence  of  either  of  these  a  charcoal  fire,  covered  with 
an  iron  plate,  is  commonly  used,  and  another  very  clean  and 
convenient  method  is  to  make  the  end  of  a  flat  bar  of  iron  red 
hot,  and  to  pinch  the  bar  in  the  vice,  placing  the  work  at  some 
distance  from  the  heated  extremity,  and  gradually  advancing  it 
as  the  bar  cools. 

Vessels  filled  with  boiling  water  or  steam  are  sometimes 
employed  ;  these  are  very  cleanly  and  suitable,  as  there  is  no  risk 
of  excess  of  heat.  Tubes  are  sometimes  heated  in  the  same 
manner  for  lackering,  by  filling  them  with  boiling  water,  the 
ends  being  temporarily  stopped  with  corks.  Small  pieces  not 
having  many  holes  are  sometimes  dipped  into  clean  boiling  water, 
the  principal  portion  of  which  is  shaken  off  when  the  work  is 
removed,  and  the  remainder  speedily  evaporates.  In  lackering 
the  heads  of  a  large  number  of  small  screws,  they  are  frequently 
all  inserted  in  a  piece  of  card,  which  is  heated  over  a  charcoal 
fire  or  a  gas  flame,  and  the  whole  are  lackered  at  one  process. 
In  thin  circular  works,  the  friction  of  polishing  frequently 
suffices  to  give  the  requisite  heat,  more  especially  when  the 
milling  tool  is  used. 

In  whichsoever  way  the  heat  is  applied,  the  temperature  of 
boiling  water  should  not  be  exceeded,  as  excess  of  heat  is  liable 
to  discolour  the  work  by  oxidation  before  it  is  lackered,  for 


LACKERING    FLAT    WORKS.  1408 

which  there  is  no  remedy  but  repolishing;  or  if  this  evil  does 
not  occur,  the  heat  may  evaporate  the  spirit  so  rapidly  as  not  to 
allow  time  for  laying  the  lacker  on  evenly;  or  it  may  be  sufficient 
to  cause  the  boiling  of  the  lacker,  and  in  this  case  the  surface 
will  present  small  dots,  caused  by  the  bubbling  of  the  spirit. 
Should  failure  arise  from  either  of  these  causes,  the  lacker  may 
be  removed  for  another  trial,  by  wiping  off  the  first  coat  while  it 
is  still  warm  with  a  rag  moistened  with  spirits  of  wine,  but  to 
remove  lacker  after  it  has  become  hard,  it  is  generally  necessary 
either  to  apply  emery  paper,  or  to  boil  the  work  in  a  ley  of  pearl- 
ash  and  water. 

After  the  work  has  been  heated  it  is  wiped  with  a  piece  of 
clean  rag,  and  it  should  not  afterwards  be  touched  with  the 
fingers,  which  might  communicate  some  trifling  grease  or  dirt, 
but  the  temperature  is  generally  sufficient  to  prevent  the  appli- 
cation of  the  naked  hand  ;  advantage  is  therefore  taken  of  any 
small  hole  that  may  happen  to  be  in  the  work,  and  a  screw  tap, 
a  broach,  or  an  arbor,  is  inserted  to  serve  as  a  handle. 

For  flat  works,  the  lacker  is  applied  in  much  the  same  manner 
as  spirit  varnishes  are  applied  to  flat  surfaces,  but  owing  to  the 
employment  of  heat  the  lacker  sets  much  more  rapidly,  and  as 
only  a  very  thin  coating  of  lacker  is  required,  the  process  is 
generally  completed  at  one  operation.  Some  care  and  expe- 
dition are  therefore  necessary  to  lay  the  lacker  uniformly  on  the 
work,  but  being  thinner  than  spirit  varnish  it  flows  more  freely, 
and  does  not  require  to  be  worked  to  expel  air  bubbles. 

The  lackering  is  generally  commenced  at  one  edge  of  the 
work,  and  the  strokes  of  the  brush  are  taken  in  parallel  lines 
from  side  to  side ;  the  surface  generally  receives  two  coats  of 
lacker  in  immediate  succession,  and  when  the  works  are  small, 
the  first  coat  is  always  completed  before  the  second  coat  is 
commenced,  but  in  large  surfaces,  the  two  coats  are  sometimes 
carried  on  simultaneously,  the  first  being  a  small  distance  in 
advance ;  but  this  requires  to  be  done  expeditiously,  or  otherwise 
the  extreme  edge  of  each  coat  will  be  liable  to  dry  while  the 
other  is  in  progress,  and  the  surface  when  finished  will  show 
streaks  wherever  this  has  occurred ;  it  is  therefore  the  better 
practice  to  continue  the  first  coat  entirely  over  the  whole 
surface  at  the  one  operation,  and  if  necessary  the  metal  may  be 
!  reheated  for  the  second  coat. 


i 


1409  MANAGEMENT    OF    THE    BRUSH LACKERING 


on 


The  success  of  the  process  depends  however  very  much  upon 
the  good  condition  of  the  brush,  and  its  being  kept  uniformly 
moistened  with  the  lacker.  Camel  hair  brushes  are  always 
used  for  lackering,  round  brushes  about  one  quarter  of  an  inch 
diameter  are  employed  for  small  works,  and  larger  round  or  flat 
brushes  are  used  for  those  of  greater  size.  They  should  always 
be  kept  quite  clean  and  soft.  When  the  lacker  is  in  frequent 
use,  it  is  generally  kept  in  a  small  bottle,  the  cork  of  which  is 
perforated  to  fit  the  handle  of  the  brush,  which  is  thus  sus- 
pended just  above  the  lacker  when  not  in  use  ;  in  this  manner 
the  brush  may  be  kept  in  tolerable  condition  for  some  time.  If 
however  the  brush  is  only  used  occasionally,  it  is  a  better 
practice  to  wipe  it  as  dry  as  possible  on  a  clean  rag  after  use, 
and  immediately  wash  it  in  a  little  clean  spirits  of  wine,  which 
may  be  added  to  the  lacker  to  compensate  for  that  lost  by 
evaporation,  and  the  brush  may  then  be  laid  by  for  future  use. 
It  must  also  be  remembered  that  the  heat  of  the  work  speedily 
thickens  the  lacker  in  the  brush,  which  soon  becomes  stiffened, 
and  leaves  streaks  on  the  work;  This  inconvenience  is  frequently 
experienced  even  in  going  over  a  single  large  surface  ;  it  is 
therefore  a  good  method  in  lackering  large  works  to  dip  the 
brush  in  clean  spirits  of  wine,  and  wipe  it,  either  against  the 
edge  of  the  vessel,  or  a  central  wire  fixed  across  its  mouth,  before 
taking  a  fresh  supply  of  lacker.  Or  if  this  is  thought  too 
troublesome,  the  brush  should  at  any  rate  be  dipped  sufficiently 
deep  in  the  lacker  to  cover  the  hairs,  and  then  be  wiped  against 
the  cross  wire,  to  reduce  the  quantity  and  mingle  the  fresh 
lacker  with  that  previously  contained  in  the  brush. 

The  quantity  of  lacker  taken  in  the  brush  depends  partly 
upon  the  experience  of  the  operator ;  those  who  have  had  much 
practice  are  enabled  to  use  the  brush  tolerably  full  of  lacker, 
which  under  proper  management  flows  freely  over  the  surface ; 
but  those  who  have  less  experience,  will  be  more  likely  to  succeed 
when  the  brush  is  only  moderately  moistened,  as  any  irre- 
gularities in  its  application  are  then  less  apparent. 

Circular  works  are  generally  lackered  in  the  lathe,  and  when 
the  friction  of  polishing  is  not  sufficient  to  give  the  necessary 
temperature,  the  arbors,  screw  chucks  or  other  apparatus 
necessary  for  fixing  the  work  in  the  lathe,  are  laid  in  order 
ready  for  use,  after  having  been  wiped  clean  with  whitening  as 


CIRCULAR    WORKS.       DIPPING    AND    BRONZING.  1410 

carefully  as  the  work  itself.  The  work,  when  sufficiently  healed, 
is  rapidly  transferred  to  the  lathe,  finally  wiped  with  a  clean 
cloth,  and  lackered  with  a  rather  dry  brush,  which  is  gradually 
traversed  along  the  work  while  the  lathe  is  slowly  turned  in 
the  direction  to  lay  the  hairs  straight.  The  brush  should  be 
traversed  twice  over  every  part  of  the  work  to  ensure  its  being 
uniformly  covered  with  the  lacker ;  should  this  not  be  the  case, 
the  surfaces  will  frequently  exhibit  prismatic  colours  when 
examined  from  different  points  of  view. 

The  lackers,  whether  pale  or  coloured,  are  applied  in  the  same 
manner  to  all  works  either  plain  or  ornamented,  but  for 
mechanism  the  pale  lackers  are  almost  exclusively  used,  and  the 
coloured  lackers  are  principally  applied  to  works  of  an  orna- 
mental character,  with  the  view  of  giving  a  richer  tint  to  the 
metal  than  it  naturally  possesses.  }n  some  instances  the  colour 
is  produced  entirely  by  the  lacker,  as  in  wood,  or  leather,  which 
are  sometimes  covered  either  with  silver  leaf  or  tin  foil,  and 
afterwards  coated  with  a  gold-coloured  lacker.  This  constitutes 
a  sort  of  fictitious  gilding  that  is  tolerably  durable,  but  dis- 
appears on  the  application  of  alcohol  or  naphtha. 


Ornamental  works  in  brass,  such  as  house  furniture,  lamp  and 
gas  fittings,  whether  stamped  or  cast,  are,  as  mentioned  on  page 
1041,  generally  brightened  and  coloured,  by  dipping  and 
bronzing,  which  processes  will  be  here  briefly  described. 

After  the  works  have  been  fitted  together,  they  are  annealed 
by  heating  them  over  the  open  fire  to  the  red  heat,  and  allowing 
the  cooling  to  extend  over  one  or  two  hours ;  but  if  the  works 
should  have  been  brazed,  a  longer  time  is  allowed  for  the  cooling. 
The  heat  employed  in  annealing  removes  any  grease  or  dirt  that 
may  have  accumulated  during  the  processes  of  fitting ;  but 
annealing  is  inadmissible  with  works  that  have  been  soft  soldered, 
as  the  heat  would  melt  the  solder,  and  therefore  such  works  are 
i  annealed  before  they  are  fitted  together,  and  are  afterwards 
boiled  in  a  ley  of  pearl  ash  to  remove  the  grease. 

The  work  is  next  pickled  in  a  bath  of  dilute  aquafortis,  which 
|may  be  made  with  two  or  three  parts  of  water  to  one  of 
juafortis  ;  but  the  old  acid  that  has  been  used  for  dipping,  and 

VOL.  III.  C  C 


DIPPING    BRASS    WORKS. 


, 

rm 


contains  a  small  quantity  of  copper  in  solution,  is  frequently 
preferred.  The  work  is  allowed  to  remain  in  the  pickle  for  one 
or  two  hours  according  to  the  strength  of  the  acid  ;  but  the 
metal  must  not  be  permitted  to  remain  in  the  pickle  for  too  long 
a  time,  or  it  will  be  eaten  into  holes.  The  entire  surface  of  the 
work  is  next  scoured  quite  bright  with  sand  and  water,  applied 
with  an  ordinary  scrubbing  brush  ;  the  work  is  then  washed  and 
allowed  to  remain  in  quite  clean  water  for  a  few  minutes  until 
the  dipping  bath  is  ready. 

The  dipping  bath  consists  of  pure  nitrous  acid,  commonly  known 
as  dipping  aquafortis,  a  sufficient  quantity  of  which  is  poured  into 
a  glass  or  earthenware  vessel  to  allow  of  the  work  being  entirely 
covered  with  the  acid,  so  far  as  the  process  is  required  to 
extend.  If  the  work  does  not  require  to  be  wholly  immersed,  it 
is  handled  with  the  fingers,  but  if  the  entire  surface  is  to  be 
dipped,  brass  pliers  are  used,  as  the  insertion  of  wood  or  iron 
instruments  would  deteriorate  the  acid. 

The  bath  having  been  prepared,  the  work  is  taken  out  of  the 
water  and  dipped  into  the  aquafortis  for  an  instant  only ;  it  is 
then  quickly  removed,  plunged  into  clean  water  and  well  rinsed 
to  remove  the  acid,  for  which  purpose  two  or  three  vessels 
containing  cold  water  and  one  hot  water  are  arranged  in  order, 
and  the  work  is  transferred  from  one  vessel  to  another  as  rapidly 
as  possible,  in  order  to  prevent  its  being  discoloured  during  its 
passage  through  the  air.  The  more  effectually  to  remove  the 
acid,  some  manufacturers  add  argal  to  the  hot  water. 

If  the  work  should  not  appear  sufficiently  bright,  it  may  be 
dipped  a  second  time,  but  the  work  must  be  quickly  removed 
from  the  acid,  as  it  acts  very  energetically  on  the  metal,  and  the 
dipping  must  not  be  repeated  too  frequently,  or  a  bad  colour 
will  result,  which  can  only  be  remedied  by  cleaning  the  surface  a 
second  time.  Immediately  after  the  rinsing,  the  work  is  plunged 
into  dry  beech  or  box  wood  saw-dust  and  rubbed  until  quite  dry. 
The  work  is  then  burnished  at  the  parts  required  to  be  bright, 
and  lackered  with  as  little  delay  as  possible  to  prevent 
discoloration. 

The  green  bronze  colours,  in  imitation  of  the  tints  that  occur 
on  real  bronze  from  long  exposure  to  the  atmosphere,  are 
produced  chemically  on  brass  and  gun-metal,  by  a  variety  of 
acid  applications,  but  in  all  it  is  quite  essential  that  the  work 


BRONZING    BRASS    WORKS.  1412 

should  be  first  thoroughly  cleaned  from  grease,  and  brightened 
either  with  the  file  or  emery  paper,  in  order  to  allow  the  acid  to 
act  uniformly  on  the  surface.  Works  having  ornamented  sur- 
faces to  which  the  file  or  emery  paper  could  not  be  conveniently 
applied,  are  generally  boiled  in  a  ley  of  pearlash,  and  afterwards 
scoured  with  clean  sand  and  water. 

Sometimes  vinegar  alone  is  used  as  the  bronzing  liquid,  at 
other  times  dilute  aquafortis,  or  a  strong  solution  of  sal 
ammoniac  is  used;  but  more  frequently  sal  ammoniac  and  vinegar 
are  employed  together,  in  the  proportions  of  from  one  to  three 
ounces  of  sal  ammoniac  to  a  pint  of  vinegar,  according  to  the 
taste  of  the  operator,  and  sometimes  a  little  common  salt  is 
added. 

A  cheap  but  tedious  bronze  is  made  by  dissolving  half  a 
pound  of  sal  ammoniac  in  a  quart  of  dilute  nitrous  acid,  say  one 
part  of  aquafortis  to  two  of  water ;  this  takes  about  two  hours 
before  the  colour  is  fully  developed.  A  better  and  quicker 
bronze  is  made  with  one  ounce  of  corrosive  sublimate  dissolved 
in  one  pint  of  vinegar ;  this  requires  about  a  quarter  of  an  hour 
to  produce  the  colour.  The  best  and  most  rapid  bronzing 
liquid,  but  the  most  expensive,  is  however  the  nitromuriate  of 
platinum,  called  chemical  bronze ;  with  this  liquid  the  required 
effect  is  produced  in  two  or  three  minutes.  The  solutions  are 
all  employed  in  the  same  manner;  the  work  having  been 
thoroughly  cleaned,  is  equally  wiped  over  with  the  bronzing 
liquor,  and  this  is  allowed  to  remain  until  it  ceases  to  act  on 
the  metal,  which  should  then  appear  nearly  black.  Sometimes 
to  assist  the  action  of  the  acid  the  work  is  slightly  warmed,  and 
if  necessary  a  second  or  third  coat  of  the  bronzing  liquid  is 
applied.  The  work  is  then  dusted  over  with  common  black 
lead,  and  brushed  like  a  stove  to  give  it  a  good  gloss. 

With  the  view  of  rendering  the  action  of  the  bronzing  liquid 
as  uniform  as  possible,  small  articles  are  sometimes  dipped  in  the 
acid  ;  for  larger  articles,  the  bronzing  liquid  is  sometimes  dabbed 
on  plentifully  with  a  piece  of  rag  tied  to  a  stick,  in  order  to 
avoid  the  appearance  of  streaks,  which  sometimes  occur  when 
the  bronze  is  applied  with  straight  strokes.  In  some  cases,  as 
soon  as  the  nearly  black  colour  appears  to  be  sufficiently  deve- 
loped, the  work  is  rinsed  in  clean  water  to  prevent  the  further 
action  of  the  acid  on  the  metal,  which  is  afterwards  dried  and 

cc2 


1413  APPLICATION    OP    HARD-WOOD    LACKER 


blackleaded.  In  other  cases  the  bronzing  liquid  is  plentifully 
covered  with  black  lead,  in  order  to  distribute  it  more  equally, 
and  the  work  is  then  allowed  to  remain  until  nearly  dry  before 
it  is  brushed. 

The  work  is  finally  lackered  in  the  ordinary  manner  ;  but  the 
green  lacker,  coloured  with  tumeric,  as  mentioned  in  page  1396, 
is  employed  to  produce  the  green  tint  usually  seen  on  bronzed 
works.  The  colour  of  the  bronze  depends  in  great  measure  upon 
that  of  the  lacker,  and  should  the  latter  be  too  green,  the  colour 
is  modified  by  the  addition  of  pale  lacker  in  different  proportions, 
according  to  the  tint  required.  But  although  the  green  lacker 
will  communicate  a  green  tint,  it  is  quite  essential  that  a  nearly 
black  surface  should  have  been  previously  produced  by  the 
bronzing  liquid,  and  upon  which  the  depth  and  perfection  of  the 
colour  primarily  depend. 

The  quality  of  the  metal  has  also  some  influence  on  the  colour 
of  the  bronze,  and  on  this  account  it  is  rather  difficult  to  make 
the  colour  uniform  when  the  works  consist  partly  of  cast  and 
partly  of  sheet  metal,  as  the  latter  does  not  readily  take  so  dark 
a  tint  from  the  bronzing  liquid. 

In  works  partly  dipped,  and  partly  bronzed,  the  latter  is  the 
final  process. 


Hard-wood  lacker,  or  polish,  is  applied  to  turned  works  in  the 
following  manner.  The  work  having  been  turned  as  clean  and 
smooth  as  possible,  and  rubbed  with  fine  glass  paper,  as  men- 
tioned at  page  1123,  a  thin  rubber  is  made  of  three  or  four 
thicknesses  of  soft  linen  rag,  merely  laid  over  each  other,  and 
a  few  drops  of  the  hard-wood  lacker  prepared  as  directed  at 
page  1392,  are  placed  on  the  center  of  the  rag  either  by  a  brush, 
or  by  covering  the  mouth  of  the  bottle  with  the  rag  and  shaking 
them  together ;  a  single  thickness  of  rag  is  then  put  over  the 
lacker,  and  a  drop  or  two  of  linseed  oil  is  placed  on  the  center 
of  the  rag  immediately  over  the  lacker. 

The  rubber  is  then  applied  with  light  friction  over  the  entire 
surface  of  the  work  while  revolving  in  the  lathe,  never  allowing 
the  hand  or  the  mandrel  to  remain  still  for  an  instant,  so  as  to 
spread  the  lacker  as  evenly  as  possible,  especially  at  the  com- 


TO    TURNED    WORKS.       FRENCH    POLISHING.  1414 

meneement,  and  paying  particular  attention  to  the  internal 
angles,  so  as  to  prevent  either  deficiency  or  excess  of  lacker  at 
those  parts.  The  oil  in  some  degree  retards  the  evaporation  of 
the  spirit  from  the  lacker,  and  allows  time  for  the  process ;  it 
also  presents  a  smooth  surface,  and  lessens  the  friction  against 
the  tender  gum.  When  the  lacker  appears  dry,  a  second,  third, 
or  even  further  quantities  of  lacker  are  applied  in  the  same  man- 
ner, working,  of  course,  more  particularly  upon  those  parts  at  all 
slighted  in  the  earlier  steps.  After  a  little  practice  this  will  be 
found  a  quick  and  easy  process,  but  when  convenient  it  is  always 
desirable  to  repeat  the  process  after  the  expiration  of  a  few  days, 
as  the  lacker  will  by  that  time  be  partly  absorbed,  especially  in 
the  end  grain  of  the  wood,  which  is  more  porous,  and  should 
therefore  receive  a  larger  proportion  of  lacker  in  the  first 
application. 

For  common  works,  the  lacker  and  oil  are  frequently  both 
placed  on  the  same  surface  of  rag.  In  this  case  the  oil  is  first 
applied  to  the  rag,  and  the  lacker  is  then  added ;  but  this 
method,  although  more  rapid,  does  not  produce  so  even  a  sur- 
face as  when  the  lacker  is  covered  with  a  single  thickness  of 
oiled  rag,  through  which  the  clearer  portions  alone  percolate 
gradually. 

French  polish  is  applied  to  flat  surfaces  in  nearly  the  same 
general  manner  as  hardwood  lacker  is  applied  to  turned  works. 
As  previously  mentioned,  the  only  difference  between  ordinary 
French  polish  and  hardwood  lacker  is,  that  the  former  contains 
rather  a  larger  proportion  of  spirit,  which  is  adopted  principally 
in  order  that  the  French  polish  may  spread  more  easily,  and  dry 
less  rapidly  upon  flat  surfaces,  which  are  generally  larger  than 
turned  works,  and,  therefore,  require  more  time  in  polishing, 
especially  as  the  friction  is  derived  exclusively  from  the  motion  of 
the  hand. 

The  rubbers  used  in  French  polishing  are  made  in  a  variety  of 
methods,  according  to  the  fancy  of  the  polisher,  and  the  size  is 
of  course  proportioned  to  that  of  the  work,  but  they  seldom 
exceed  three  inches  diameter.  The  small  cloth  or  list  rubbers 
mentioned  in  Article  5,  p.  1090,  are  very  generally  employed 
ifor  French  polishing,  especially  in  laying  on  the  first  coat ;  and 
'it  is  mostly  preferred  that  the  list  should  be  torn  off  the  cloth, 
las  this  makes  the  edge  softer  than  if  it  were  cut.  Sometimes 


1415 


FRENCH    POLISHING. 


the  rubber  is  covered  with  a  piece  of  linen  rag  upon  which  the 
lacker  is  applied ;  at  other  times  the  rag  is  omitted,  and  the 
lower  face  of  the  rubber  itself  is  saturated  with  lacker,  in  order 
to  soften  that  which  may  remain  in  the  rubber  from  previous  use, 
and  the  excess  is  squeezed  out  before  commencing  the  polishing. 
These  rubbers  often  serve  for  several  months'  use. 

At  the  opposite  extreme  of  durability  are  the  small  rubbers, 
made  of  wadding,  as  mentioned  in  Art.  6,  p.  1090,  that  are 
thrown  away  after  a  few  minutes'  use ;  but  this  is  by  many  con- 
sidered to  be  very  wasteful,  both  of  wadding  and  lacker,  and 
they  therefore  adopt  a  medium  course,  and  use  one  wadding 
rubber  for  five  or  six  hours.  In  this  case  the  wadding  is  first 
picked  to  loosen  it  thoroughly,  and  any  knotted  pieces  are 
rejected;  the  wadding  is  then  thoroughly  saturated  with  the 
lacker,  and  squeezed  moderately  dry,  so  as  to  leave  a  quantity  of 
lacker  proportioned  to  the  size  of  the  work.  The  wadding  is 
then  placed  in  the  middle  of  a  piece  of  soft  linen  rag,  which  is 
gathered  up  at  the  back  and  tied.  Sometimes  a  piece  of  sponge 
is  used  in  the  same  manner ;  this  forms  a  durable  rubber,  but  of 
course  it  requires  to  be  softened  every  time  before  use. 

The  choice  of  rubber,  however,  depends  principally  upon  habit, 
and  is  nearly  immaterial,  provided  the  rubber  is  moderately  soft, 
and  contains  a  sufficient  quantity  of  lacker  to  allow  of  its  being 
gradually  supplied  to  the  work  as  the  polishing  progresses ;  but 
it  is  at  all  times  necessary  that  the  rubber  should  be  covered 
with  a  piece  of  soft  rag,  moistened  with  a  few  drops  of  oil,  and 
renewed  as  often  as  it  becomes  so  far  clogged  up  as  to  prevent 
the  lacker  passing  freely  through  it,  or  that  any  portion  of  the 
lacker  on  the  surface  has  become  so  hard  as  to  be  likely  to  scratch 
the  half  dry  and  tender  polish. 

The  work  having  been  thoroughly  smoothed  with  fine  glass 
paper,  and  the  dust  wiped  away  with  a  clean  cloth,  the  polishing 
is  commenced  with  free,  continuous,  and  uniform  circular  strokes, 
applied  with  very  light  pressure,  and  gradually  traversed  over 
the  whole  surface  ;  and  the  same  process  is  continually  repeated, 
varying  the  position  of  the  strokes  as  much  as  possible,  but 
keeping  them  about  the  same  size,  and  taking  care  that  every 
portion  of  the  surface  receives  an  equal  but  not  excessive  quantity 
of  lacker,  which  is  regulated  partly  by  the  degree  of  pressure  on 
the  rubber,  and  partly  by  squeezing  it  between  the  fingers. 


FRENCH    POLISHING.  1416 

The  principal  points  requiring  attention  are,  that  the  pressure 
is  moderate  and  uniform,  that  the  circular  strokes  are  taken 
regularly  over  the  whole  surface,  and  that  the  rubber  is 
never  allowed  to  remain  stationary  on  the  work,  or  be  lifted 
directly  from  it.  Should  the  pressure  be  too  great,  it  would  be 
liable  to  disturb  the  smooth  surface  of  the  tender  lacker  already 
applied,  and  should  the  pressure  or  the  strokes  be  irregular,  a 
thicker  coat  of  lacker  would  be  given  at  some  parts  than  at 
others.  Should  the  rubber  be  allowed  to  remain  stationary  on 
the  work,  it  would  be  liable  to  adhere  to  the  surface,  which 
would  be  injured  on  its  removal,  and  the  same  injury  would  be 
liable  to  occur  if  the  rubber  were  lifted  directly  from  the  surface, 
and  therefore  in  removing  the  rubber  it  should  be  slid  off  at  the 
sides  or  ends  of  the  work,  or  if  taken  from  the  middle,  it  should 
be  done  with  a  sweeping  stroke,  so  as  to  lift  the  rubber  gradually 
while  in  motion.  Circular  strokes  are  adopted  instead  of  straight 
strokes,  partly  because  the  grain  of  the  wood  is  filled  up  quicker 
and  more  uniformly,  but  principally  in  order  to  avoid  the 
blemishes  which  would  be  almost  certain  to  occur  at  the  end  of 
every  stroke  taken  backwards  and  forwards,  unless  the  rubber 
were  every  time  traversed  entirely  off  the  end  of  the  work,  which 
is  not  generally  convenient. 

The  process  of  polishing  is  continued  until  the  grain  of  the 
wood  appears  to  be  thoroughly  filled  up,  and  the  surface  exhibits 
a  uniform  appearance,  well  covered  with  a  thin  coat  of  lacker. 
It  is  then  allowed  to  stand  for  an  hour  or  two  to  become 
thoroughly  hard,  when  it  is  rubbed  with  very  fine  glass-paper  to 
smooth  down  all  the  irregularities  of  the  grain  of  the  wood,  and 
also  of  the  lacker.  The  polishing  is  then  repeated,  and  if  it 
should  be  found  necessary  it  is  again  smoothed,  and  the  polishing 
is  persevered  in  until  the  surface  appears  quite  smooth,  and 
uniformly  covered  with  a  thin  and  tolerably  bright  coat  of 
lacker,  but  which  will  nevertheless  show  cloudy  marks  from  the 
rubber,  owing  to  the  presence  of  the  oil,  which  is  finally  removed 
with  a  few  drops  of  spirits  of  wine  applied  on  a  clean  rubber  and 
covered  with  a  clean  soft  linen  rag,  with  which  the  work  is 
rubbed  with  very  light  strokes,  applied  first  with  a  circular 
motion,  and  when  the  surface  appears  nearly  dry,  straight  strokes 
are  taken  lengthways  of  the  grain  of  the  wood,  and  traversed 


1417  INDIAN    VARNISHES.        BURMESE    WARE. 

entirely  off  the  ends  of  the  work ;  this  is  continued  until  the 
rubber  and  work  are  both  quite  dry,  when  the  polishing  will 
be  completed. 

The  polish,  however,  will  be  partly  absorbed  by  the  wood  in 
the  course  of  a  day  or  two ;  and  therefore  it  is  desirable  to 
repeat  the  process  after  the  lapse  of  a  few  days,  first  slightly 
rubbing  down  the  former  coat  with  very  fine  or  nearly  worn-out 
glass-paper,  as  it  is  essential  to  a  smooth  and  durable  surface 
that  the  ultimate  body  of  polish  should  be  as  thin  as  possible. 

The  intricate  parts  of  carved  work  that  cannot  be  rubbed 
smooth  as  explained,  are  varnished  with  white  hard,  or  brown 
hard  varnishes,  applied  with  the  brush  as  usual;  but  the  body  of 
varnish  should  be  as  thin  as  possible,  particularly  in  the  angles 
and  edges  of  delicate  works,  or  otherwise  the  character  of  the 
work  will  be  greatly  deteriorated.  The  brown  hard  varnish  is 
much  harder  than  the  white,  and  from  its  lesser  transparency  it 
does  not  require  quite  so  much  care. 


In  India,  a  thin  liquid  balsam,  obtained  by  incision  from  the 
Dipterocarpus  terminatus,  and  one  or  two  other  trees,  is  com- 
monly known  under  the  name  wood-oil,  and  is  extensively 
employed  as  a  varnish  for  general  purposes,  and  also  for  the 
Burmese  cups  and  similar  ware.  For  common  purposes  the  var- 
nish is  laid  on  with  a  brush,  as  usual ;  but  for  the  Burmese  ware, 
the  second  and  subsequent  coats  of  varnish  are  laid  on  and 
smoothed  with  the  naked  hand,  both  in  order  to  preserve  a  fine 
surface  and  to  enable  the  workman  to  discover  and  reject  any 
minute  particles  of  dirt.  When  first  laid  on,  the  varnish  appears 
of  a  light  brown  colour,  but  rubbing  with  the  hand  changes  it 
to  a  fine  black.  When  the  articles  have  been  varnished,  they 
are  carefully  shut  up  in  a  box  to  exclude  the  dust,  and  then 
deposited  in  a  deep  cold  vault  for  at  least  three  days,  which 
treatment  is  said  to  be  essential  to  the  proper  hardening  of  the 
varnish. 

The  Burmese  cups  of  small  size  are  made  of  thin  strips  of 
bamboo  woven  together  like  fine  basket-work,  and  after  the  first 


BURMESE    WARE.        FURNITURE    POLISH.  1418 

coat  of  varnish,  the  interstices  of  the  basket-work  are  filled  up 
with  a  paste,  made  of  wood-oil  mixed  with  different  fine  powders, 
such  as  calcined  bones  or  very  fine  saw-dust  from  teak  wood. 
After  the  paste  is  smoothed  with  the  hand,  the  article  is  again 
returned  to  the  cold  vault,  and  when  it  is  sufficiently  hardened, 
the  surface  is  smoothed  with  pumice  stone  and  water ;  the  cups 
are  afterwards  varnished  three  or  four  times,  and  finally  polished 
after  the  same  general  methods  as  are  adopted  in  this  country 
for  varnished  works. 

Sometimes  the  cups  are  ornamented  with  raised  figures,  which 
are  made  of  the  same  paste  that  is  used  to  fill  up  the  interstices 
of  the  basket-work ;  the  paste  is  pressed  into  tin  moulds,,  and 
afterwards  transferred  to  the  bowls ;  when  dry  it  becomes  hard 
as  solid  wood.  At  other  times  the  cups  are  ornamented  with 
engraved  designs,  which  are  afterwards  filled  up  with  different 
coloured  powders  mixed  with  wood-oil,  after  which  the  surface  is 
smoothed  with  wet  bran  held  in  the  hollow  of  the  hand;  the 
operation  is  generally  repeated  to  insure  the  complete  filling  up 
of  all  the  lines,  and  the  cups  are  afterwards  varnished  and 
Dolished  as  usual. 

A  very  good  varnish  is  prepared  by  the  Moochees  with  shell- 
ac and  wood-oil,  heated  and  mixed  in  small  quantities.  They 
also  prepare  a  varnish  for  palanquins  by  melting  sandarach  and 
mixing  it  with  boiled  linseed  oil  rendered  drying  with  litharge, 
but  they  do  not  usually  add  spirits  of  turpentine  in  the  manner 
generally  adopted  in  England  for  making  oil  varnishes.  To  give 
the  appearance  of  gold  to  the  silver  leaf  used  by  the  Candapilly 
Moochees  for  ornamenting  boxes,  palanquins,  and  similar  objects, 
a  little  aloes  is  dissolved  in  the  varnish,  which  is  laid  over  it. 

J.  Rhode,  Esq.,  of  Madras,  from  whose  notes  the  above  parti- 
culars were  gathered,  says,  "  I  know  of  no  better  or  more  durable 
polish,  for  teak  or  furniture  woods,  than  may  be  prepared  by 
melting  three  or  four  pieces  of  sandarach  of  the  size  of  a  walnut 
or  small  egg,  and  pouring  upon  it  a  bottleful  of  linseed  oil  ren- 
dered drying  by  litharge  or  other  drier,  and  after  boiling  them 
together  for  an  hour,  gradually  adding  while  cooling  a  teaspoon- 
ful  of  Venice  turpentine.  If  too  thick,  it  may  be  thinned  with 
spirits  of  turpentine.  It  should  be  rubbed  on  the  furniture,  and 
after  a  little  time,  during  which  it  may  be  exposed  to  the  sun, 


1419 


FURNITURE    POLISH. 


rubbed  off;  the  rubbing  should  be  repeated  daily,  and  the  polish 
should  not  be  again  applied  for  eight  or  ten  days,  after  which  it 
may  be  slightly  applied  every  one  or  two  months.  Water 
does  not  injure  this  polish,  and  any  stain  or  scratch  may  be 
rubbed  over  with  the  polish,  which  cannot  be  done  with  French 
polish." 


END    OF    THE    THIRD    VOLUME. 


INDEX. 


VOLS.   I.   TO   III. 


A. 


ABELE.     See  POPLAR,  102. 

Abraham,  Mr.,  methods  for  obviating  un- 
healthiness  of  dry  grinding,  1112. 

Abrasion,  general  remarks  on  the  figuration 
of  materials  by,  1179. 

Abrasive  materials,  see  GRINDING  and  PO- 
LISHING; analyses  of,  1029. 

Abrasive  processes.  See  GRINDING  and 
POLISHING.  General  observations,  abra- 
sive and  cutting  processes  compared, 
1027. 

Acacia  wood,  71. 

Acraman,  Messrs.,  large  cupola  for  melting 
iron,  367. 

Adamantine  spar.     See  CORUNDUM,  1049. 

Adams,  Messrs.,  bow  springs  for  carriages, 
251. 

Admiralty  Museum,  collections  of  woods  in, 
68. 

Adze,  mode  of  action  and  application  of ; 
Indian  adze,  473. 

African  black-wood.     See  BLACK  BOTANY- 
BAY  WOOD,  74. 
—      ivory,  138. 

mahogany,  92. 
oak,  96. 

Agate,  general  uses  of,  1 72. 

-  cut  and  polished  like  carneliau,  1033. 

-  staining,  1339. 

Aikin,  Mr.  A.,  on  ox  and  stag  horn,  126;  on 
timber  and  ornamental  woods,  64  ;  on 
whalebone,  136. 

Airo-hydrogen  blowpipe,  454. 

Alabaster,  general  characters  of,  and  modes 
of  working,  164. 

—  cleaning   works   in,    164,   1034, 

1200. 

—  lapidary's   methods   of  working, 

1034. 

polishing  and  smoothing  sculp- 
tured and  carved  works  in, 
1033. 

polishing  turned  works  in,  1034. 
t  Ubata,  composition  of.     See  NICKEL,  279. 

polishing  spoons,  &c.,  of,  1036. 
Ubumen  in  bones  and  shells,  117. 
Ucohol,  concentrating,  for  varnish  making, 
1379. 


Alcohol,  qualities  of,  as  a  vehicle  for  var- 
nish, 1378. 

Alder- wood  (Alnus  glutinosa),  71. 

Allan,  Mr.,  method  of  originating  screws, 
581 ;  cutting  micrometer  screws  with  dies, 
647. 

Allen,  Mr.,  drill- stock  for  small  drills, 
556. 

Alloy-balance  by  Mr.  Roberts,  298. 

Alloying,  soldering,  tinning,  water-gilding, 
and  zincing,  examples  of,  300 — 301. 

Alloys,  antimony  and  lead,  277. 

—  atomic   proportions   of,  difficult    in 

ordinary  practice,  286. 

—  bismuth,  267. 

—  brass,  loss  of  zinc  in,  314  ;  partially 

prevented  by  charcoal,  316. 
copper,  266  ;  variety  and  dissimi- 
larity of,  294  ;    experiments   on 
alloys  of  copper  with   lead,    tin, 
and  zinc,  313. 

—  copper  and  lead,  271. 

—  copper  and  nickel,  279. 

—  copper  and  silver,  282. 

—  copper  and  tin,  '269. 

—  copper  and  zinc,  269. 

—  copper,  zinc,  tin,  and  lead,  272. 

—  Eckart,  Dr.  Von,  platinum,  281. 

—  fusibility  of,  300. 

—  fusible,  266. 

—  gold,  274. 

—  hardness,  fracture,  and  colour  of,  2  92. 

—  iron,  368. 

—  lead  and  antimony,   277  ;    general 

characters  of,  293. 

—  lead  and  copper,  271  ;  general  cha- 

racters of,  294. 

—  lead  and  tin,  284 ;  melting  heats  of 

435. 

—  malleability  and  ductility  of,  295. 

—  metallic    unions  as    soldering    ex- 

amples of,  303. 

—  metals  all  capable  of  forming,  302. 

—  mixing  metals  of  different  degrees 

of  fusibility  for,  310. 

—  nickel  and  copper,  279. 

—  nickel,  used  in  Richardson  and  Brai- 

thwaite's  patent  mode  of  tinning, 
451. 
palladium,  279. 


1421 


INDEX. VOLS.    I.    TO    III. 


Alloys,  pewter,  284;  Babbet's  patent  anti- 
friction metal,  .970. 
platinum,  281. 

—  platinum  and  gold,  276. 
proportions  of  metals  varied  accord- 
ing to  their  purity,  300. 

qualities  of,  frequently  differ  from 
their  constituents,  292. 

—  silver,  282. 

silver  and  platinum,  281. 

—  strength  or  cohesion  of,  297. 
tables  of  the  cohesive  force  of,  289. 

—  tables  of  proportion  of,  299,  1024. 

—  tin,  284. 

—  tin  and  copper,  269  ;  their  general 

characters,  294. 
tin,  copper,  lead,  and  zinc,  272. 

—  zinc,  286. 

• —  zinc  and  copper,  267  ;  comparative 
loss  of  zinc  in  small  quantities, 
313. 

—  zinc,  copper,  lead  and  tin,  272. 
Almond-tree  wood  (Amygdalus  communis), 

72. 

Aloes-wood.     See  CALEMBEG,  78. 
Alumina,  base  of  corundum,  emery,  ruby, 

&c.,  1036. 
Amalgam,   used  by   dentists   for   stopping 

teeth,  970. 
Amber,  general  treatment  of,  161. 

—  polishing,  1036. 

—  qualities  of,  as  a  basis  for  varnish, 

1374. 

—  varnish,  1387. 
Amboyna-wood,    see  KIABOOCA-WOOD,   88  ; 

probably  a  burr  of  a  timber- tree,  38. 
American  maple- wood,  93. 
Amethyst,  cut  and  polished  like  carnelian, 

1036. 
Analyses  of  grinding  and  polishing  materials, 

1029. 

—       of  iron  and  steel,  236. 
Angica-wood.     See  CANGICA-WOOD,  78. 
Angle  joints  for  sheet-metals,  391. 
Anime,  qualities  of,  as  a  basis  for  varnish, 

1374. 

— -      varnish,  1386. 

Annales  de  Chimie  et  de  Physique,  116, 236. 
Annealing,  235. 

brass  for  dipping,  &c.,  1410. 
cast-iron,  260. 
glass,  237. 
sheet-iron,  976. 

steel,  effects  of  different  treat- 
ment, 238. 

steel   plates   for     transfer    en- 
graving,   decarbonizing   pro- 
cesses, 254. 
steel    rapidly,    by    intermittent 

cooling,  242. 

wrought-iron  bars  greatly  in- 
creases their  tenacity  ;  Mr.  Nasmyth's 
experiments,  461. 


Annersley,  Mr.,  patent  method  of  building 

vessels,  29. 
Antelope  horn,  122. 

Antimony,  general  characters  and  uses  of 
265. 

—  cohesive  force  of,  288. 

—  expansion  in  cooling,  application 

of  the  property,  293. 
Antimony    alloys,    general    characters    of, 

293;  cohesive  force,  289. 
Anvils  for  forging  ordinary  works,  208. 

—  stakes  and  teests  for  working  sheet- 

metals,  386. 

—  and  hammers   covered    with   cloth, 
for  sheet-metal  work,  411. 

Apple-tree  wood  (Pyrus  Malus),  72. 
Apricot- tree    wood    (Armeniaca,   vulgaris), 

72. 

Aquamarine,  1037. 
Araucaria   excelsa    (Norfolk  Island   pine), 

37. 

Arbor  vitse  wood,  72. 
Archery  bows,  31. 
Areca  catechu  nut,  111. 
Arm-rest  for  turning,  522. 
Artist's  copal  varnish,  1385. 
Ash- wood,  73. 
Ash,  Mr.,  patent  screw   auger  with  guide, 

1002. 
Asiatic  ivory,  138. 

—  Society's     Museum,     collection     of 
woods  in,  68. 

Aspen.     See  POPLAR,  102. 
Asteria.     See  SAPPHIRE,  1091. 
Astragal  planes,  489. 

—       tools  for  turning  hard  woods,  519. 
Attalea  funifera  nut,  111. 
Augers,   screw,    543;    Ash's    patent, 

guide,    1002  ;   Cook's,    1002 

square  holes,  544. 

—  shell,  540. 

—  single-lip,  543. 
Authors  on  turning,  4 — 8. 
Avanturine,   real,  fictitious,  and   artificial, 

1037. 
Averuncator,    for    pruning     young    trees, 

912. 

Axe,  mode  of  action  of,  472. 
Ayr-stone  for  polishing,  1065. 


13. 


BABBAGE, CHARLES,  Esq.,  F.R.S.,  cutter-bars 
or  tool-holders  for  turning  and  planing 
metal,  987  ;  with  many  blades,  for  planing 
metal,  990  ;  for  turning  wood,  989 ; 
face-cutter,  with  many  blades,  for  the 
lathe,  991  ;  paper  on  the  principles  o: 
tools  for  planing  and  turning  metals, 
984. 

Babbet's  patent  anti-friction  metal  for  bear- 
ings of  machinery,  970. 


INDEX. — VOLS.    I.    TO    III. 


1422 


Backs  for  supporting  specula,  1275,  1288. 
Back-stays  for  cutting  long  slender  screws 

in  the  lathe,  634. 
Baker,  Capt.  H.  C.,  on  Indian  timber  woods, 

31  ;  ebony,  84  ;  saul-wood,  106. 
Balance,  Roberts's  alloy,  298. 
Balls,  Guy's  method  of  grinding  accurate 
spheres  of  hardened  steel,  glass,  &c.,  1257. 
Bamboos,  their  growth  and  structure,  1 7  ; 

general  uses,  98. 
Bancroft,  Dr.,  on  greenheart,  or  the  Sipiera- 

tree,  86. 

Banding  plane,  488. 
Barberry  wood  (Berberis  vulgaris),  73. 
Barclay,  Mr.  H.,    patent  artificial   emery- 
stone  for  grinding   wheels   and  rubbers, 
1057. 

Barton,  Sir  John,  double  shearing-machine, 
920 ;  engraved  steel  buttons,  showing 
prismatic  colours,  42,  646  ;  method  of 
originating  screws  with  chain  or  steel 
band,  645. 

Bar- wood  used  as  a  red  dye  wood,  73. 
Bass,  Mr.,  method  of  sharpening  knives  in 

his  cork-cutting  machine,  1113. 
Bassoolah,  or  Indian   adze,  for   preparing 

turnery  woods,  473,  953. 
Bath  metal,  composition  of,  268. 
Bay-tree  (Laurus  nobilis),  73. 
Bead  planes  and  astragal  planes,  imperfec- 
tions of,  489. 

—  tools  for  turning  hard  woods,  519. 
Beak-irons,  for  working  sheet-metal,  387. 
Beech-wood  (Fagus  sylvatica),  73  ;  sections, 

showing  general  structure  of  woods,  14. 
Beef-wood.     See  BOTANY-BAY  OAK,  75. 
Bell-founding,  363  ;  metal,  composition  of, 

270. 

Bellingham,  Mr.  H.,  plane-iron,  498. 
i  Bellows  for  forging,  200,  202,  231. 
Bench,  jewellers'  and  silversmiths',  731. 
joiners'  planing,  494 
holdfasts  for,  495. 
hooks  and  stops  of  ordinary  con- 
struction  for,  494  ;   Franklin's 
screw  hook  for,  979. 
screws  and  stops,  of  ordinary  con- 
struction for,  495. 
stops  and  clamps,  by  Mr.  De  Beau- 
fort and  Mr.  S.  Nicholls,  for,  979. 
lapidaries',    or    grinding    machine, 

1 305. 
planes,    general     proportions    and 

structure  of,  476. 
vice,  for  filing,  855. 
iBeuding  and  flattening   rollers   for   sheet- 
metals,  389. 

boiler-plates,    Mr.  Roberts's    ma- 
chine for,  390. 
ribs  of  iron  ships,  394. 
thin  sheet-metals,  387. 
timber  for  ship  and  bridge  build- 
ing, shafts,  &c.,  32. 


Bentham,     General,    planing-machine    for 

wood,  503 
Berthoud,  M.  F.,  description   of  old  fusee 

engine,  with  inclined  plane,  638. 
Beryl,  wrought  and  engraved  like  carnelian, 

1037. 

Besson's  screw-cutting  lathe,  616. 
Betel-nuts,  or  areca-nuts,  general  uses  and 

characters  of,  111. 
—        polished   with    glass-paper  and 

whiting,  1 037. 
Bethell,  Mr.,  on  the  preservation  of  woods, 

459. 

Bevil  tools  for  turning  hard  woods,  518. 
Bevils  for  metal  works,  881. 
Biddery-ware,  composition  of  the  metal  of, 

286. 

Billiard  balls,  precautions  to  prevent  shrink- 
age of,  152. 

tables,  of  mahogany  and  slate,  57. 
Bilston  grindstones,  1064. 
Birch-wood  (£etula),  74. 
Birdlime  prepared  from  holly,  87. 
Birmingham   sheet-metal   and   wire  gages, 

values  of,  in  decimal  parts  of  the  inch,  101 3. 
Bisecting  gage  for  wood,  488. 
Bismuth,  general  characters  and  uses  of, 265. 
cohesive  force  of  bismuth  and  its 

alloys,  288, 289;  expansion  in  cooling,293. 
Bitter-nut-wood,  74. 
Black  Botany-Bay  wood,    or  African  black 

wood,  74  ;  irregular  and  wasteful  growth 

of,  24. 

Black  wood-tree  (Dalbergia  latifolia),  83. 
Blasting  granite,  practice  at  the  Foggintor 

quarry,  1 70. 

Blazing  off,  saws  and  springs,  250. 
Bleaching  ivory,  153. 

—  lac  varnishes,  1393. 
Blister  steel,  manufacture  of,  191. 
Blocks,  Brunei's  mortising  and  scoring  en- 
gine for  ships',  505. 

—       or    rubbers,  for  polishing   marble, 
1089,  1199. 

Bloodstone  employed  for  burnishers,  1037. 
Blowpipes,  general  applications  and  forms 

of,  437. 

airo-hydrogen,  454. 
bellows  and  gas  flame,  439. 

—  flame,  different  degrees  of  heat, 

438. 

furnace,  Gill's  portable,  441. 
gas,  439. 

glassblowers',  for  toys,  440. 
lamps  used  with,  for  soldering, 

439. 

supports,  charcoal,  444;  pumice- 
stone,  978  ;  wire  matting,  439. 
table  and  workshop,  440. 
Blue  gum-wood.     See  GUM-WOOD,  86. 
Blue  polishing-stone,  1066. 
Boards,  clamping  wide,  to  prevent  warping, 
707. 


1423 


INDEX. VOLS.    I.    TO    III. 


Boards,  contraction,  splitting,  and  warping  of, 
50. 

—  glueing  the  edges  of,  59. 

—  planing,  498. 

—  sawing,  707. 

Bob  used  for  polishing  the  bowls  of  spoons, 

1038. 
Bodmer,  Mr.  G.,  patent  method  of  forging 

tires  for  wheels  of    locomotive  engines, 

1021  ;  patent  screw-stocks,  606  ;   patent 

tap  for  internal  screws,  585  ;  screw  tool 

for  slide-rests,  629. 
Body  varnish  for  carriages,  1386. 
Bohemian  polishing-stone,  used  by  jewellers, 

1067  ;  analysis  of,  1029. 
Boilers,  angle-joints  for,  392. 

bending  boiler  plates,  Mr.  Roberts's 

machine  for,  390. 
Boiling  and  clarifying  linseed  oil  for  varnish 

making,  1377. 
Bolter,  Mr.,  on  woods,  65. 
Bolts,  forging  screw,  213. 

—  screwing  machines  for,  607. 

Bone,  analysis  and  preparation  of,  117 — 120. 

—  dust  used  for  case-hardening,  261. 

—  polishing  bone-works,  1038. 
Boring  tools  and  processes,  539  : — 

Archimedian  drill-stocks,  1003. 

Ash's  patent  screw  auger,  with  guide, 

1002. 

Auger,  American  screw,  544  ;  with 
guide,  1002. 

—  bit  for  brace,  450. 

—  screw,  543. 

—  shell,  540. 

—  single  lip,  543. 

—  square  hole,  544. 
Boring-bits,  brush,  540. 

Cornish,   with    loose   cut- 
ters, 1007. 

cylinder,  565. 

flat,  for  cast  iron,  566. 

German,  for  wood,  544. 

half  round,  565. 

Holtzapffel's,  with  change- 
able cutters,  1006. 

Kittoe's  expanding,  1009. 

Maudslay's,  with   change- 
able cutters,  1008. 

Ordnance,  for  boring  guns, 
567. 

rose,  for   finishing   holes, 

565. 

Boring  cylinders,  for  steam-engines, 
&c.,570;  G.Wright, inventor 
of  tlie  modern  system,  1010. 

—  :  enlarging  holes  by,  566. 

—  flutes  and  clarionets,  542,  572. 

—  granite  with  jumper,  170. 

• —  machines,  of  various  construc- 
tions, with  revolving  and 
sliding  cutter  bars  and  blocks, 
for  large  works,  569 — 572. 


Boring  tools  and  processes  : — 

Boring  mineral  substances,  170,  552. 

—  pipes  for  gas  and  water,  558, 

1004. 

—  stone,  180,  543,  1208,  1320. 
Brace,  angle,    545  ;  carpenters',  545  ; 

corner,  561  ;  smiths',  557  ;  smiths' 
expanding,  560. 
Broaches  compared  with  drills,  575. 

—  gun-barrel,  575. 

—  parallel,  474. 

—  polygonal,  round,  and  twisted, 

573. 

—  taper,  572. 

—  with  detached  blades,  574. 

—  wood  rimers,  572. 
Brush  boring-bits,  540. 

Button  tool  for  cutting  leather  disks, 

541. 

Center-bit,  common,   plug,  and    wine- 
coopers',  541. 
—          expanding,  ordinary,  542; 

Franklin's,  1001. 
hard  wood,  for  finger-holes 

in  flutes,  &c.,  542. 
Cherries,  for  bullet-moulds,  549. 
Clamp  drill  frames,  558. 
Collas's  lathe  drill,  1006. 
Cooper's     boring-bits,     545  ;     cent 

bit,  541 ;  dowel  bit,  539;  rimer,  57; 
Corner  drill  frames,  561. 
Countersink,    cone,  549  ;    drill,    548 ; 
square,   548,  550  ;    with   detached 
blades,  574. 

Cutlers'  expanding  drill,  1006. 
Cutter    bars,    with    detached    blades, 
for  boring  steam  cylinders,  cutting 
grooves,    mouldings,    recesses,    and 
screws,  569 — 572. 
Cutters,  hinge  or  knuckle-joint,  894. 

—      pin,  and  drills,  550. 
Cylinder  boring-bit,  565. 
Drill,  action  of,  compared  with  broach, 
575. 

—  annular  drills,  or  grinders,  180. 

—  Archimedian  drill-stocks,  1003. 

—  bow  and  breast-plate,  553. 

—  clamp  drill-frame,  558. 

—  Collas's  lathe,  1  006. 

—  comparison  of  single  and  double 

cutting,  for  metal,  549. 

—  corner,  561. 

—  countersink,  548. 

—  cup-key  tool,  for  flutes,  &c.,  542. 

—  cutlers'  expanding,  547. 

—  dentists'  rectangular  drill  stocks, 

1003. 

—  diamond,  for  china,  glass,  &c.,  180. 

—  differential  screw,  562. 

—  double  cutting,  with  pointed, 

cular,  and  flat  ends,  547. 

—  flute,  for  finger-holes,  542  ; 

mers,  572. 


INDEX. VOLS.    I.    TO    III. 


1424 


Boring  tools  and  processes  :  — 
Drill,  Freeman's  tool,  1002. 

—  grinding,  1140. 

—  harpmakers'   drilling  apparatus, 

563. 

—  horn  and  tortoiseshell,  548. 

-     lapidaries'    small     and    tubular, 
1320. 

—  lathe,  for  metal,  564,  1005;  for 

wood,  542. 
lever,  560. 
lubrication  of,  for  metal,  552. 

—  mineral,  552. 

—  Nasmy th's  portable  hand,  568. 

—  ornamental  drills  and  cutters  for 

wood,  ivory,  &c.,  1173. 
• —     passer,  for  inlaying,  135. 

—  pin     drills     and     cutters,     550, 

892. 

—  pump,  557. 

—  press  frame,  old,  557  ;   modern, 

558. 

—  rachet,  and  lever,  561. 

—  re-centering,  for  deep  holes,  549, 

567. 

—  Roberts's  pin,  55 1 . 

—  Shank's  differential  screw,  562. 

—  sharpening  drills  and   revolving 

cutters  for  ornamental  turn- 
ing, 1167. 

—  single-cutting,  for  metals,  548. 

-  socket  for  lengthening,  561. 

—  spring  passer,  for  inlaying,  1 35. 

—  Stivens's  expanding  lathe,  1008. 

—  stocks  for  small  drills,  common, 

Gill's,  555  ;  Sir  J.  Robison's, 
Allen's,  &c.,  556. 

—  stocks,  dentists'  rectanglar,  1003. 

—  stone  drills  and  cutters,  180,  543, 

1208,  1320. 

—  stop,  549. 

—  Swiss,  547. 

—  tubular  drills,  or  grinders,  180 

1320. 

—  watchmakers',  553. 

-  wood,  542,  1173, 

Drilling  and  boring  machines,  563. 

—  deep  and  small  holes,  567. 
enlarging  holes  by,  566. 
glass  and  earthenware,  179. 

—  holes   with    templets  in   hare 

plates,  891. 
jewels,  1 79. 

—  lathe  for  ordinary  works,  563 

for  small  drills,  555. 

—  methods  of  working  drills  bj 

hand-power,  small  drills 
with  drill-bow,  553 ;  me 
dium-sized  drills  with  brace 
557;  large  drills  with  lever 
ratchet,  pinion,  and  differ 
ential  screw,  drills,  frame, 
or  stocks,  560. 


Coring  tools  and  processes  : — 

Drilling      mineral     substances,     180, 
552. 

—  pipes  for  water  and  gas,  558  ; 

Mr.    G.  Scott's  apparatus, 
1004. 

—  vertical,  machines  for,  567. 
Duck-nose  bits,  540. 

German  boring-bit  for  wood,  544. 
Gimlet,  common,  541;  twisted,  543. 

•  Gouge-bits,  539. 

Guides  for  wood-boring  tools,  540. 

Miser  for  boring  earth,  552. 

Pump-bits,  540. 

Quill-bits,  539. 

Rimers  for  wood,  572. 

Table-bits,  539. 

Wine-coopers'  center-bit,  541 ;  rimer, 
573. 

Wire-workers'  awl,  539. 
3otanical   names  of  woods.      See  WOODS, 

Botanical  names. 
Botanical  notes  on  wood,  by  Dr.  Royle,  65. 
Botany-Bay  oak,  75. 
Bow  saw,  738. 
Bows  for  archery,  31. 
Box,  construction  of  a  dove-tailed,  54,  721. 

-  glueing  up  a,  60. 

Boxwood  (Buxus  sempervirens),  76. 
Brace,  angle,  545;  carpenters',  54 5  ;  corner, 
561 ;  smiths',    557  ;   smiths'   expanding, 
560. 
Bradawl,  569. 

Braithwaite's    patent    process  for  tinning 
metallic  vessels,  451 ;  patent  process  for 
imitating  wood-carving,  459. 
Bramah,  Mr.  T.,  planing  machine  for  wood, 

504. 

Brande,  T.  W.,  Esq.,  on  metals,  265,  290. 
Brass,  composition  of  various  kinds,  268  ; 
remarks  on,  273  ;  various  methods 
of  mixing  the  metals,  311;  Emer- 
son's patent,  312  ;  ordinary  mode, 
314;  loss  of  zinc  in  remelting, 
315. 

—  lacker  for,  1 395. 

—  lackering  ordinary  works  in,  1 406  ; 

bronzed  works,  1413. 

—  pickling    works     for     dipping    and 

bronzing,  1410. 

—  polishing  cast  and  stamped  works  for 

house  furniture,  1041. 

—  common  and  superior  flat  works 

in,  1039. 

—  curling  flat  surfaces,  1039. 

—  door-plates,  1039. 

—  tumed  works,  1038. 
watchwork,  1040. 

Brazier's  works,  polishing,  1040. 
Brazil  wood  (Ccesalpinia  ecliinata),  77. 
Brazilian  pebbles.     See  QUARTZ,  1050. 
Brazilletto  wood  (Ccesalpinia  braziliensis),  77. 


1425 


INDEX. VOLS.    I.    TO    III. 


Britannia  metal,  composition  of,  285,  31 1 
polishing,  1041. 

British  plate,  composition  of,  279  ;  polish- 
ing, see  ALBATA,  1036. 

Broaches,  compared  with  drills,  575. 

—  gun  barrel,  575. 
parallel,  474. 

polygonal, round,  and  twisted,  573. 

taper,  572. 

with  detached  blades,  574. 

wood  rimers,  572. 
Broaching  machines,  575. 
Broads  for  turning  soft  wood,  515. 
Bronze  metal,  composition  of  antique  and 

modern,  269. 

Chantrey's  and  Keller's,  272. 
Bronzing  brass  works,  1411. 

—  lackering  bronzed  works,  1413. 

—  liquids,  1412. 

Brown,  Major,  on  Norfolk  Island  pine,  37. 
Brown-hard  spirit  varnish,  1392. 
Brunei,  Sir  M.  I.,  cutter  bar  for  iron,  535  ; 
mortising  engine  for  ships'  blocks,  505  ; 
scoring   engine   for  ships'    blocks,   506  ; 
vertical  saw  machine,  747. 
Brush  boring-bits,  540. 
Brushes,  polishing,  1041. 

scratch,  1122. 
—         wheel,  1122. 
Buck  horn,  121;  straightening,  957. 
Buckum  wood.     See  SAPAN-WOOD,  105. 
Buff  leather  and  buff  sticks,  for  polishing, 
1042. 

wheels,  for  polishing,  1118. 

Buffalo  horn,  122. 

Buhl   cutting,    ordinary    practice    in    two 
thicknesses  of  wood,  733  ;  in 
three  thicknesses,  735. 
brass,  and  pearl  shell,  736. 

—  counterpart,  735. 
internal,  736. 

Buhl  polishing  works  in,  1079. 

—  printing  patterns  from,  735. 

—  saws  and  frames,  732  ;    methods  of 

setting  out  and  sharpening  the  teeth 
of,  692. 

—  sawing-horse,  732. 

—  sawing-machine,  by  Mr.  M'Duff,  747. 

—  stamping  or  punching,  works  in  brass 

and  wood,  737,  749. 

Bullet  moulds,  320. 
—    wood,  77. 

Bullets  found  in  elephants'  tusks,  145. 

Burmese     bowls,     &c.,     manufacture     of, 
1417. 

Burnett  and  Foyer,  Messrs.,  planing  ma- 
chine for  wood,  981. 

Burnishers,    general    forms,    action,    and 
application  of,  1042. 

—  agate,    bloodstone,    and     flint, 

1037. 

for    sharpening    comb-makers' 
floats,  838. 


Burnishing  or  spinning  teapots,  rings,  and 

other  circular  works  in  sheet  metal,  395. 
Burrowes,  Mr.  J.,  on  mosaic  works  in  wood, 

764. 
Bursill's    cutting  pliers,    with     removable 

cutters,  906. 
Buttons,  engraved  steel,  showing  prismatic 

colours,  42,  646. 
Button- wood  tree.     See  PLANE-TREE,  101. 


C. 


CABBAGE-WOOD.     See  PARTRIDGE-WOOD,  99. 
Cabinet  varnish,  1386. 
Cable  chains,  manufacture  of,  226. 
Calamander.     See  COROMANDEL,  82. 
Calculating  angles  of  screw  threads,  657. 
Calembeg  (Aquilaria),  78. 
Calemberri.     See  COBOMANDEL,  82. 
Caliatour,  an  Indian  red  wood,  40. 
Callipers  cut  out  of  sheet  metal  with  the 

chisel,  918. 

Cameo,  carving  shell,  1094. 
Cameo  cutting,  1365. 

—  adaptation  of  the  design  to  the  stone 

1367. 

—  onyx,  application  of  the  term,  1366 

—  spade  for  smoothing,  1368. 
Campeachy  logwood.     See  LOGWOOD,  91. 
Camphor- wood  (CampJiora"),  78. 
Cam-wood  (Baphia  nitida),  78  ;   durability 

of  colour  of,  45. 

Canary-wood  (Laurus  indicoC),  78. 
Cangica-wood,  78. 
Cannel   coal,    general   treatment   of,    162 

polishing,  1043. 
Capping-plane,  493. 
Caps,  or  metal  laps,  with  wooden  centers, 

1044. 
Carbon,  extreme  hardness  of,  1044.      See 

also  CHARCOAL,  1047;  and  DIAMOND,  1205. 
Carbonate  of  lime  in  bones,  &c.,  118. 
Carbuncle,  1044. 
Carnelian,  general  treatment  of,  172  ;   co- 
loured by  heat,  &c.,  1338. 
—        lapidaries'   routine  for   cutting, 

grinding,  smoothing,  and  polishing,  1044. 
Carriage  varnish,  1387. 
Carving  alabaster  ornaments,  164. 

—  Braithwaite's  patent  mode  of  imi- 

tating, 459. 

—  cameos  in  conch  shell,  1094. 

—  colour  of  material  should  be 

form,  45. 

—  floats  for  ivory,  See.,  838. 

—  imitated  by  embossing  and  mould- 

ing, 45  ;   by  indenting,  46  ;  by 
burning,  459. 

— -      ivory  busts,  by  Mr.  B.  Cheverton, 
140. 

—  ivory  with  small  circular  sa\ 

cutters,  753. 


INDEX. VOLS.    I.    TO    III. 


1426 


Carving  machines,  Gibb's  patent,  employed 
principally  for  wooden  letters, 
1025. 

Irving's  patent,  employed  princi- 
pally for  mouldings,  954. 

—  J ordan's  patent,  employed  princi- 

pally for  figures  and  ornaments, 
954. 

Tomes's  patent  dentifactor,  for 
carving  artificial  gums,  palates, 
and  teeth,  955. 
Case-hardening,  260. 

Casks,  cutting  staves  for,  Sir.  J.  Robison's 
and  Mr.  Smart's  methods,  804  ;  Taylor's 
patent  machinery,  32. 
Casting.     See  FOUNDRY  WORK. 

—  clichee,  324. 

—  laps,  or  metal  wheels  for  polishing, 

1115. 

—  lead  grinders  for  cylindrical  holes, 

1247;  rods,  1233. 

—  lead  pipes,  278,  431  ;    sheet   lead, 

277 ;  shot,  278. 

—  organ  pipes,  270. 

—  plate  glass,  1218. 
ast-iron.     See  IRON,  CAST. 

—  manufacture  of,  182. 
ast-steel.     See  STEEL,  CAST. 

—  manufacture  of,  192. 

atalogue  of  grinding  and  polishing  appa- 
ratus, materials,  and  pro- 
cesses commonly  employed 
in  the  mechanical  and  useful 
arts,  1033. 

metals  and  alloys,  commonly 
employed  in  the  mechanical 
and  useful  arts,  265. 
woods,  general  characters  and 
uses  of  those  commonly  employed  in  this 
country,  65. 
at's-eye,  1046. 

Mils   for  glueing,  flat  works,  61;    curvi- 
linear works,  62. 

edar  wood  (Jwniperw,  Cedrela,  &c.),  79. 
/ement,  diamond,  or  isinglass,  155  ;    Sir  J. 
Robison's  method  of  preparing, 
957. 

—  iron,  for  filling  joints,  454. 
lapidaries',  1312. 

—  opticians',  1265. 
turners',  160. 

enter-bit,  common,  plug,  and  wine-coopers', 
541. 

—  expanding,        ordinary,     542  ; 

Franklin's,  1001. 

—  hard  wood,  for  finger  holes  in 
flutes,  &c.,  542. 

Chains,  forging  ordinary  and  cable,  226. 

punching  flat  links  of  chains,  for 
machinery,  watches,  jewellery,  &c.,  539. 
Chalcedony,  1046. 

halk,  analysis  of,  1029  ;    preparation  of, 
'  for  polishing,  1046. 


Chamois  horn,  122. 

Change    wheels    for    screw-cutting,    621  ; 

modes  of  computing  trains,  626. 
Charcoal,    application    of,     for    polishing, 

—  iron,  manufacture  of,  187. 
Charnley  Forest  stone.     See  HONE  SLATES, 

1065. 

Chasing  metal  works,  413  ;  Szentepeteri's 
specimen  in  alto-rilievo,  414. 

—  tools  for  threads  of  screws,  angular, 
628  ;  rounded,  629  ;  square,  630. 

Cherries  for  bullet  moulds,  549. 
Cherry-tree  wood  (Cerasus),  80. 
Chesnut  wood  (Castanea  vesca),  80. 
Cheverton,  Mr.  Benjamin,  ivory  carvings, 

140. 
Chidson,  Mr.,  table  for  proportions  of  small 

screws  of  angular  threads,  671. 
Chinese  planes,  478. 

—  sensitive  leaves  of  horn,  1 23. 
Chipping  metal  works  preparatory  to  filing, 

850. 
Chisel  chipping,  850. 

—  cross-cutting  and  flogging,  851. 
-    file  cutters',  827. 

key-way,  with  guide-block  for  wheels 
and  pulleys,  885. 

—  mortise,  application  of,  716. 
paring,  474 ;  grinding,  1138;  sharpen- 
ing, 1144. 

—  rasp-cutters',  830. 

—  turning,  for  soft  wood,  512;  grinding, 

11 38;  sharpening,  1145. 
Chrysoberyl,  1048. 
Chrysolite,  or  peridot,  1048. 
Chrysoprase,  1048. 
Chucking  cannel  coal,  163. 

—  eggshells,  156. 

—  ivory  in  rough  blocks,  149. 

—  mineral  substances,  163. 
Chucks  for  small  circular  saws,  752. 
Circle,  simplicity  and  truth  of,  2. 
Circular  saws.     See  SAWS,  CIRCULAR. 
Cissampelos  Pareira,  16. 

Citric   acid   used   for  cleaning   egg   shells, 

159. 

Clamping  wide  boards,  55. 
Clamps,  dovetail,  56. 

—  screw,  for  glueing,  61. 

—  vice,  for  filing,  859. 

Clarifying  linseed  oil,  for  varnish  making, 

1377. 

Clark,  Dr.,  on  meerschaum,  161. 
Clay,  Mr.,  patent  process  for  manufacturing 

wrought  iron,  958. 

Clay,  ordinary  modes  of  working,  160. 
• —     Prosser's   patent   process   for  works 

made  of  dry,  957. 
Cleaning    alabaster,    164,    1034 ;     marble, 

1200. 
Cleaver     for     preparing    turnery     woods. 

25. 


1427 


INDEX. VOLS.    I.    TO    III. 


Clement,  Mr.,  finishing  tools  for  planing  and 
turning  brass  and  iron,  537  ;  originating 
guide  screws,  648 ;  screw  tool  for  slide  rests, 
629;  straightening  cylindrical  shafts,  426. 

Clichce  casting,  324. 

Clifford's  patent  methods  of  rolling  and 
punching  nails,  949. 

Cloth  polishers  for  ordinary  works,  1048. 

—  rubbers     for     marble     and    French 

polishing,  &c..  1089. 

—  tools  for  polishing  lenses,  1211,  1267. 

—  wheels  for  polishing  lapidaries'  work, 
ivory  handles,  &c.,  1121. 

Cock,  Mr.  W.,  on  palladium,  279. 
Cocoa-nut  palm  (Cocos  nucifera),  see  PALM 

TREES,  97  ;  sections  of,  17. 
—       shell,  111. 
Cocoa-wood,  or  cocus,  80. 
Coffee-tree  wood  (Coffca  arabica),  81. 
Cohesive  force  of  metals  and  alloys,  287. 
Coin,  correctional  process  in  drawing  metal 

bars  for,  428. 

Coining  presses,  936 ;  punches,  938 ;  dies,  255. 
Colcothar  of  vitriol.     See  OXIDE  OF  IRON 

1082. 

Cold-short  iron,  189,  460. 
Collas,  Mr.,  lathe  drill,  1006. 
Colophony,  or  common  resin,  its  qualities  as 

a  basis  for  varnish,  1376. 
Colthurst,  Mr.  J.,  experiments  on  the  force 
required  to  punch  holes  in  copper  and 
wrought  iron,  951. 
Comb-making : — 

Dyeing  horn  in  imitation  of  tortoise- 
shell,  126. 

Floats,  837;  quannet,  838. 
Machines   for   cutting   teeth   of  bone, 
ivory,  and  wood  combs,  794  ;   horn 
and  tortoiseshell,  931. 
Parting  horn  and  tortoiseshell  teeth,  1 30. 
Saws  ;  circular  saws,  794;  double  saw, 
or  stadda  723;  gage-saw  orgagevid, 
724. 

Soldering  tortoiseshell,  130. 
Combe,  Mr.,  on  elephants'  tusks,  146. 
Compass,  lock,  and  table  saws,  711. 

—  plane,  475. 
Congleton  gritstone,  1064. 

Conical  surfaces,  production  of,  by  abrasion, 

1251. 
Continental  fire-wood  sawing-machine,  740; 

sawing-horse,  727. 
Cook's  patent  for  forging  wrought-iron  tubes 

for  gun  barrels,  &c.,  965. 
Cooper's   boring   bits,    545  ;    croze,    408  ; 

planes,  478  ;  sun  plane,  488. 
Copal,  qualities  of,  as  a  basis  for  varnish, 
1375. 

—  spirituous  solutions  of,    1375,  1394. 

—  varnishes,  1385. 
Cope  of  loam  moulds,  359. 

Copper,  general  characters,  uses,  and  alloys 
of,  266. 


Copper,  cohesive  force  of,  288. 

—  white, composition  of,  279. 
Copper   alloys,  variety  and  dissimilarity  of, 

294. 

—  cohesive  force  of,  289. 
Copper  and  lead  alloys,  271. 

Copper  and  tin  alloys,  269  ;  cohesive  force 

of,  297. 

Copper  and  zinc  alloys,  267. 
Copper,   zinc,  tin,  and  lead  alloys,  272. 
Copper-plates  polished  with  charcoal,  1047. 
Coppersmiths'    work,     see    SHEET     METAL 

WORKS. 

—         polishing,  1040,  1049. 
Coquilla-nut,  general  characters  and   uses 

of,  111. 

polishing,  1049. 

Coral  cutting  and  polishing,  1049. 
Coral-wood,  82. 

Cornish  boring-bits  with  loose  cutters,  1007. 
Coromandel-wood  (Diospyros  hirsuta),  82. 
Corosos,  or   ivory-nut,  general    characters 

and  uses  of  the,  112. 
polishing,  1049. 

Corundum,  analysis  of,  1029  ;  applications 
of,  for  grinding  and  polishing  wheels  and 
rubbers,  1049. 

Cottles  in  pewterers'  moulds,  320. 
Coulter's  (Dr.),  collection  of  woods,  69. 
Countersink,  cone,  549  ;  drill,  548  ;  square, 

548,  550  ;  with  detached  blades,  574. 
Cowdie,  or  New  Zealand  pine  (Dammara 
australis).     See  PJNES,  100. 

—  Expansion  of,  47. 

Cowper,  Mr.,  alloy  for  rose-engine  and 
eccentric-turned  patterns,  266. 

Cox,  Mr.,  on  woods,  65. 

Crab-tree.     See  APPLE-TREE,  72. 

Crane,  lapidaries',  for  slicing  large  stones, 
1312  ;  amateurs',  for  small  stones,  1342. 

Cranked  tools,  for  turning  iron,  526. 

Craufurd's  patent  for  galvanized  iron,  971. 

Creasing  tools  for  sheet  metal,  383. 

Crocus  for  polishing,  various  modes  of  ma- 
nufacture of.  See  OXIDE  OF  IRON,  1 082. 

Crucibles  for  founding,  management  in  the 
furnace,  308. 

Crystal  or  quartz,  application  of,  to  lenses, 
&c.,  1050. 

—  varnish,  1397. 
Crystallographical  solids  in  wood,  general 

remarks  on  the  production  of,  779. 
Cube,  sawing,  with  circular  saw,  774. 
—     sawing   crystallographical  solids   de- 
rived from  the,  780. 
Cupolas  for  melting  iron,  366. 
Cuticaem  branco  andCuticaem  vermo,  woods 

showing  silver  grain,  41. 
Cutlers'  drill  for  inlaying  handles,  135. 

—  green  hone.  See  HONE  SLATES,  1 066. 

—  grindstones  and  frames,  &c.,  1105. 

—  hammer  for  forging,  210. 

—  laps,  1114. 


INDEX. VOLS.    I.     TO    III. 


1428 


Cutlers'  leather  and  wood  wheels,  for  polish- 
ing and  glazing,  1118. 

Cutlery,  grinding  and  polishing,  general 
routine  of  the  processes  in  fine 
and  common  works,  1051. 

—  hardening  and  tempering,  245,  248. 

—  lapping,  razors,  penknives,  &c.,  1 1 5. 

—  polishing  razors   and  fine  cutlery, 

1120. 

setting  razors,  1146. 
Cutters,  circular,  for  taps,  585. 

—  semi-cylindrical,  for  ribbon-rollers, 
491. 

Cutter-bars  for  boring,  cutting  grooves,  re- 
cesses, mouldings,  &c.,  569. 

—  for  cutting  external  and  internal 

screws,  631. 

—  for   planing   and   turning,  535, 

987. 
Cutting  and  abrasive  processes   compared, 

1027. 

gage  for  wood,  487. 
pliers  or  nippers  for  wire,  905. 

—  tools.     See  TOOLS,  CUTTING. 
Cylinders,  boring  steam-engine,  570,  1010. 

casting  steam-engine,  373. 
moulding  steam-engine,  359. 
Cylindrical  holes,  grinding,  1245. 

—  rods,   imperfections  in   turning 

removed  by  grinding,  1232. 

—  shafts,  straightening,  426. 
surfaces,  production  of,  by  abra- 
sion, 1232. 

Cypress-tree  (Cupressus),  83. 


D. 


).EDALUS,  supposed  inventor  of  turning,  5. 
)alton,  Dr.,  on  ductility  and  malleability  of 

metals,  376. 

)amar,  qualities  of,  as  a  basis  for  varnish, 
1376. 

—       varnishes,  1397. 
)amascus  gun-barrels,  224. 
)avison,   Capt.    G.  D.,    rectangular  drill- 
stock  for  dental  surgery,  1004. 
)eakin's  patent  for  working  horn,  126. 
)eal  woods.     See  PINES,  100. 
3e   Beaufort's   vice   or   stop    for   planing- 

benches,  980. 
)enison,  Lieut.,  experiments  on  American 

timbers,  30. 

)ent,  Mr.  E.  J.,  on  watch-springs,  252. 
)entifactor    for    carving    artificial    gums, 

palates,  and  teeth,  patented  by  Mr.  Tomes, 

955. 
>entists'    amalgam    for   stopping   decayed 

teeth,  970. 
drill-stocks,  1003. 
wheels  and   rubbers  of  Barclay's 
I    artificial  emery-stone  for,  1057. 
revonshire  batts.     See  GRINDSTONE,  1 064. 


Devonshire  oilstone.  See  HONE  SLATES,  10  66. 
Diamond,  analysis  of,  1029  ;  its  general 
treatment  and  uses,  175. 

bort,  176. 

cement,  154. 

—  crystallisation  of,  177. 
drills,  179. 

—  etching,  180. 

—  fictitious,  1053. 

—  glaziers',  action  of,  176. 

—  grinding  tools,  179. 

—  lenses,  175. 

powder,  preparation  of,  for  use 
of  lapidaries,  seal  engravers, 
and  watch  jewellers,  1052. 

—  mortars,  for  crushing  and  grind- 

ing the,  1309. 

—  splitting,  cutting,  and  polishing, 

the,  176,  1097,  1331,1337. 
tools    for    drilling,    graduating, 
grinding,  and  turning,  178,  646. 
Dies  for  stamping  coin,  methods  of  harden- 
ing, 255. 

—  for  sheet  metals,  409,  974. 

Dies  for  cutting  screws,  593 ;  general  con- 
siderations of  curvature  and  form  of, 
599. 

—  adapted  principally  for  short  screws, 

610. 

—  Allan's  method  of  cutting  micrometer 

screws  with,  647. 

—  applications  of,  601,  607. 

—  Barton's  application  of  two  pairs,  646. 

—  Clements's  apparatus  for,  employed  in 

originating  screws,  649. 

—  compression  of,  and  correctional  modi- 

fications, 602. 

—  employment  of,  in  originating  screws, 

636. 

—  forms  of,  in  common  use,  602. 

—  interferences  of  curvature  in,  599. 

—  irregularities  of  screws  cut  with,  601. 

—  Jones's  cutters  for,  603. 

—  Keir's  cutters  for,  603. 

—  left-hand,  substitute  for,  604. 

—  Maudslay's  improvements  in,  646. 

—  proportions  of,  600  ;  medium  generally 

preferred,  602. 

—  regulating,  for  plug  taps,  676. 

—  Robison's,  603. 

—  Ross's  method  of  cutting  micrometer 

screws  with,  648. 

—  two  pairs  of,  sometimes  used,  601,  646. 
Die-stocks  for  cutting  screws,  596. 

—  Bodmer's  screw  stocks,  606. 

—  double  and  single  chamfered,  598. 

—  early  forms  of,  597. 

—  general  remarks  on  action  of,  608. 

—  modern  forms  of,  598. 

—  plier,  597. 

Whitworth's  screw  stocks,  605, 

609. 

Dipping  brass  works,  1411. 
2 


1429 


INDEX. VOLS.    I.    TO    III. 


Dividing  engine,  for  graduating  straight 
lines,  Donkin's,  651  ;  Ramsden's,  641  ; 
for  graduating  circles,  Ramsden's,  631. 

Dodd,  Mr.  J.,  on  casting  wheels,  358. 

Dodecahedron  cut  with  circular  saw,  775. 

Dog-wood  (Cornus),  83. 

Donkin,  Mr.,  circular  saw  bench  for  angular 
works,  799  ;  rectilinear  dividing  engine, 
651  ;  tube  drawing  machine,  430. 

Door  panels  and  frames,  57. 

Doublets,  or  fictitious  gems  in  two  thick- 
nesses, 340. 

Dovetail,  box,  common,  54  ;  with  tea  chest 
top,  721. 

—  clamps  for  wide  boards,  56. 

—  cutting,  with  the  chisel,  719;  cut- 

ting pins  with  the  saw,  71 8. 

—  glueing,  59. 

—  joints,  mitre  and  key,  717  ;  com- 

mon, 718  ;  half  lap,  720;  lap, 
mitre,  and  secret,  721. 

—  marking,  719. 

—  saw,  713. 

—  setting  out,  718. 
Drawback,  or  false  core,  319,  338. 
Drawer  bottoms,  56. 

Drawing  knife,  474. 

—  scales  of  ivory  subject  to  contrac- 

tion, 152. 

Drawing  processes  dependent  on  ductility, 
423. 

—  metal  for  coin,  correctional  pro- 

cess, 428. 

—  mouldings  for  silversmiths'  work, 

&c.,  427. 

tubes  of  metal,  of  round,  fluted, 

square,  and  triangular  sections, 

429. 

lead  pipes,  431. 
taper  brass  tubes,  for  boilers  of 

locomotive  engines,  976. 
tin,   Rand's  process  for  patent 

collapsable    tubes     of,    431; 

superseded  by  his  method  of 

raising,  977. 

—  whalebone,  136. 

—  window  lead,  428. 

wires,    common,    423  ;    complex, 
427  ;  joint,  429  ;  pinion,  426. 
Drawplates,  fixed  rollers  employed  as,  for 

coin,  428. 
glaziers'  vice,  428. 
jewelled,  174. 
swage   bits,    for    silversmith's 

mouldings,  &c.,  427. 
tube,  and  triblets,  429  ;    with 
moveable  dies  for  square  and 
other  sections,  430. 
wire,  common,  423;  oval  and 

pinion,  &c.,  426. 

—          with  moveable  dies  for  works  of 
complex  sections,  427. 
Drifts  for  forming  holes  in  metal  of  various 
forms,  883. 


Drifts  for  forging,  217. 

Drills.     See  BORING  TOOLS. 

Drinking-horns,  manufacture  of,  123. 

Drop  for  forging,  iron,  198  ;  platinum,  280. 

Dry  grinding,  1111  ;  various  contrivances 
to  obviate  the  unhealthiness  of  the  prac- 
tice of,  1112. 

Drying-room  for  seasoning  wood,  27. 

Dry-rot,  22,  1 1 3. 

Duhamel,  M.,  Sur  1'Exploitation  desBois,64. 

Dutch  rush  for  polishing  wood  and  alabaster, 
1053, 

Dying  horn,  126. 
—    whalebone,  136. 


E. 

EAR  shells,  120. 

East  India  Blackwood  (Dalberyia  latifolia), 

83. 
East  India  House  Museum,   collection  of 

woods,  68. 
Eastman,  Mr.,   circular  saw   machine  for 

feather  edge  boards,  797. 
Ebony,  black  (Diospyros),  83  ;  green,  85 

mountain  (Baufiinice) ,  84. 
Eccentric  turning,  plain  woods  best  for,  43 ; 

sharpening  tools  for,  1164. 
Eckart,  D.  Von,  alloy  of  platinum,  silver 

and  copper,  281. 
Edwards,  Mr.,  on  woods,  65. 
Edwards,  Rev.  J.,    on   bed  of  hones   for 

smoothing   specula,    1277  ;    on  form  of 

polisher,  1278. 

Edwards's  patent  razor  strop  paper,  1 057. 
Egg  shells  cleaned  with  citric  acid.  1  57. 

—  Mr.  G.  Kittoe's  method  of  mount- 
ing, as  vases,  155. 

Egyptian  mosaics  in  glass,  767. 
Ehrenberg,  Profr.,  on  Berlin  iron  castings, 

374. 

Elasticity  of  metals,  377  ;  of  woods,  31. 
Elder  wood  (Sambucus  nigra),  84. 
Electrum,  composition  of,  279  ;   polishing, 

1054. 
Elephants'  grinders,  1 39. 

slaughter  of,  for  ivory,  141. 
• —        tusks,  their  general  characters, 
difference   in   size  and  form, 
137,  142;   bullets  found    in, 
145  ;  spear-heads,  146. 
Elm  wood  (Ulnwu),  84. 

—  toughness  of,  33. 
Elvans,  general  mode  of  working,  1 69. 

—       wrought  by  lapidaries  like  carnelian, 
1054. 

Embossed  wooden  boxes,  &c.,  45  ;  tortoise- 
shell,  133. 
Emerald,  1059. 

Emerson's  patent  for  making  brass,  312. 
Emery,  analysis  of,  1029  ;  ordinary  prepa- 
ration of,  for  grind  ing  and  polish- 
ing, 1054. 


INDEX. VOLS. 


TO    III. 


1430 


Emery,  Barclay's  artificial,  stone  for  grind- 
ing wheels  and  polishers,  1057. 

—  cake   for  dressing   cutlers'  wheels, 

1057. 

—  cloth,  1056. 

—  paper,  1056;  Edwards's  patent  razor 

strop  paper,  1057. 
sticks,  1057. 

—  washing,  in  small  and  large  quan- 

tities, for  fine  mechanical  works, 
optical  and  plate  glass,  &c.,  1055. 

—  wheels  for  polishing,  1120. 

—  white,  used  for  polishing  enamels, 
1060. 

Enamels,  general  process  of  making  and 

polishing,  1059. 
Encyclopedia     Metropolitana,      Founding, 

365  ;  tortoiseshell  press,  131. 
Endogenous  woods,  17. 
Engineers'  paring  or  slitting  machine,  for 
mortises       and      curvilinear 
works,  900. 

—  planing  machine,  896. 

—  punching  machine,  950. 

—  shaping  machine  for  circular  and 
arbitary  forms,  901. 

English  gem  engravers,  1362. 

—  treatises  on  turning,  8. 
Engraved  buttons,  Sir  J.  Barton's,  showing 

prismatic  colours,  42,  646. 
Engravers,  English  gem,  Mr.  H.  Weigall  on 

comparative  abilities  of,  1 362. 
Engraving,   copper-plate,     polishing    with 
charcoal,  1047. 

—  gem    and    seal,   general    remarks, 

1348. 

bench,  engine,  and  tools,  1349. 
adaptation  of  designs  for  cameos 

to  the  stone,  1367. 

—  charging  the  tools  with  diamond 

powder,  1354. 

cutting  cameos,  1365. 

cutting  colour  lines,  1356  ; 
curved  lines,  1360. 

cutting  escutcheon,  with  quar- 
terings,  1356  ;  flat  surfaces, 
1860. 

diamond  powder,  preparation 
for,  1052. 

mortars  for  crushing  and  grind- 
ing diamond  powder,  1309. 

—  moulds  for  conical  plugs  of  tools, 

1351. 

—  onyx,  application  of  the  term 

in,  1366. 

—  polishing  engraved  surfaces  in, 

1362. 
position  of  the  hands  in,  1358  ; 

of  the  stone,   difficulties   of 

manipulation,  1361. 
preparing  the  stones  for,  1355. 
qualities    of    different    stones 

used  in,  1363. 


Engraving  gem  and  seal,  sealing  wax  proof 
impressions  of,  1363. 

—  spade,   for  smoothing  cameos, 

1368. 

tools,  construction  of,  1354  ; 
succession  of  1357. 

wax  and  clay  for  taking  im- 
pressions in,  1347. 

—  glass,  general  remarks,  1348. 

engine    or    tool,  and    wheels, 

1369. 
general  routine  of  the  process, 

1372. 

—  Henning's  slate  moulds  in  intaglio, 
for  plaster  casts,  166. 

Envelope  cutters,  928. 

Ericcson,  Capt.,  patent  machines  for  cut- 
ting the  teeth  of  files,  841. 

Esdaile  and  Margrave's  patent  machine  for 
cutting  scaleboard,  981 ;  saw  bench  for 
cross-cutting,  795. 

Etching-diamond,  180. 

Etching  marble,  167. 

Exogenous  growth  of  wood,  15. 


F. 


FACETTING,  gold  and  silver  works,  1184. 

—  lapidary  works,  general  routine  for 

stones  of  different  degrees  of 
hardness,  1045. 

—  amateurs'  apparatus  for  cutting 

facets,  1343. 

—  Cadrans,   or   Geneva    tool,  for 

cutting  facets,  1337. 

—  different  forms  of,  1321. 

—  gim  or  germ  peg,  used  in,  1306, 

1324. 

—  steel,  jewellery,  and  beads,  1 182. 
Falconer's  circular  plough,  for  joiners,  979. 
False  core  or  drawback,  319. 

Faraday,  Dr.,  on  the  gradual  conversion  of 
cast  iron  into  plumbago,  368. 

Fauntleroy,  Messrs.,  on  woods,  65  ;  on  ivory, 
141. 

Fayrer's  swing  hone,  1060. 

Felling  saws,  700  ;  saw  machines,  739. 

Felspar,  1060. 

Felt  for  polishing.     See  CLOTH. 

Field,  Mr.  G.,  method  of  bleaching  lac  var- 
nish, 1393. 

Files,  general  and  descriptive  view  of,  of 
the  usual  kinds,  817. 

—  blanks  for,  proportions  of,  827. 

—  blunt,  taper,  and  parallel,  818. 

—  cant,  826. 

—  checkering,  827. 

—  circular,  837. 

—  cleaning,  853. 

—  cotter,  822. 

—  crossing,  823. 


14.31 


INDEX. VOLS.    I.    TO    III. 


Files,  curvature  in  length  unavoidable,  846; 
advantage  of,  868. 

—  curvilinear,  841. 

—  cutting  teeth  of,  by  hand,  827  ;  hold- 

ing the  blank,  1022. 

—  cutting    teeth     of,     by    machinery, 

Thiout's  method,  840  ;  Captain 
Ericcson's  patent  machines,  841  ; 
Sir  J.  Robison's  proposed  method 
of  cutting  the  teeth  of,  with  gravers, 
843;  inventors  of  various  file- 
cutting  machines,  1 023. 

—  double  or  checkering,  827. 

—  double  cut,  820. 

—  dovetail,  836. 

—  entering,  828. 

—  equalling,  824. 

—  feather-edged,  824. 

—  flat,  822. 

—  floats,    combmakers',     827 ;     ivory- 

carvers',  838. 

—  half  round,  823. 

—  hand,  822. 

—  handles  of,  ordinary,  823 ;  cranked,  for 

large  flat  surfaces,  834  ;  cabinet- 
makers' method  of  mounting  on 
wooden  blocks,  835  ;  handles  for 
short  files,  and  tin  or  brass  backs 
for  slender  files,  836. 

—  hardening,  253,  832. 

—  iron-founders'  rasp,  835. 

—  knife  edge,  824. 

—  Lancashire  and  Sheffield,  819. 

—  lengths  of,  818. 

—  Lund's  method  of  mounting  and  using, 

for  the  edges  of  thin  plates,  835. 

—  manufacture  of,  827. 

—  mill  saw,  825. 

—  moulding,  826. 

—  names  and  sections  of,  821. 

—  oval,  826. 

—  parallel,  blunt,  and  taper,  818. 

—  pillar,  823. 

—  quality  of,  833. 

—  quannet,  for  horn  and  tortoiseshell, 

838;  applied  to  zinc  plates,  1023. 

—  Raoul's  machine  cut,  840. 

—  rasps,  cutting  the  teeth  of,  830. 

—  rifflers,  for  sculptors,  837. 

—  Robison's     curvilinear,    formed    by 

bending,  841. 

—  round,  824. 

—  round  off,  826. 

—  rubbers,  825. 

—  safe  edge,  821. 

—  saw,  826,  689. 

—  screw-head,  826. 

—  sections  of,  longitudinal,  818 ;  trans- 

verse, 821. 

—  Sheffield  and  Lancashire,  819. 

—  short,  for  cavities  and  grooves,  836. 

—  single  cut,  820, 

—  slitting,  824. 


Files,  square,  824. 

—  styloxynon,  for   sharpening  pencils, 

827. 

—  swaged,  for  mouldings,  826. 

—  tangs,  833. 

—  taper,  blunt,  and  parallel,  81  8,  822. 

—  teeth,  819. 

—  triangular,  823. 

—  valve,  826. 

—  watchmakers',  825. 

—  White's    perpetual,    with    moveable 

plates,  839. 

Filing,  preliminary  remarks  on,  and  on  hold- 
ing works  that  are  to  be  filed, 
844. 

—  less  generally  practised  than  formerly, 

in  consequence  of  the  introduction 
of  the  planing  and  other  shaping 
machines  adapted  to  large  works, 
903. 

—  beads,  889. 

—  bevilled  edges,  881. 

—  block,  for  holding  works  to  be  filed. 

861. 

—  boards,  849,  864. 
— .     clamps,  859. 

—  comparative   sketch  of  the  applica- 

tions of  the  file  in  ;  and  of  the  engi- 
neers' planing,  paring,  slotting,  and 
shaping  machines,  896. 

—  compass  joints,  893. 

—  concave  works,  886. 

—  convex  works,  889. 

—  cork,  for  holding  small  works  to  be 

filed,  865. 

—  curling,  852. 

—  curvature  of  files,  interferences  of, 

846 ;  advantages  of,  868. 

—  curvilinear  works,  general     instruc- 

tions, 886  ;  without  templets,  888 ; 
with  templets,  890. 

—  cylindrical  pins,  862. 

—  difficulties  in,  arising  from  absence 

of  guide  in  the  instrument,  844. 

—  draw-filing,  852. 

—  drifts  for  holes  of  various  forms,  883. 

—  economy  in   method  of  using   files, 

852. 

—  flat  surfaces  under  the  guidance  of 

the  straight-edge,  and  of  the  trial- 
plate,  or  planometer,  865  ;  gene- 
ral remarks,  relative  degrees  of 
accuracy  required  for  different 
works,  869  ;  finishing  surfaces  by 
grinding,  very  impolitic,  871  ; 
finishing  surfaces  by  scraping,  868; 
originating  straight  edges  and  trial- 
plates,  or  planometers  by,  872 ; 
mutual  comparison  of  three  straight 
edges  in,  874  ;  mutual  comparison 
of  three  flat  surfaces  in,  876. 

—  gages  for  bevilled   edges,  881 ;    for 

parallel  works,  879. 


INDEX. VOLS. 


TO    III. 


1432 


Filing,  grooves  and    rebates,    angular    and 
square,  881  ;  semicircular,  886. 

—  holding   works   to   be    filed ;    large 

works  held  in  vices,  853  ;  small 
works  held  in  the  hand,  or  in  hand- 
vices,  861;  thin  works  laid  on  flat 
surfaces,  863. 

—  holes  of  various  forms,  partly  made 

with  drifts,  883. 

—  hollows,  890. 

—  joints,  knuckle  or  hinge,  for  rules, 

compasses,  &c.,  893. 

—  key-ways  in  wheels  and  pulleys,  885. 

—  management  of  the  file,  and  move- 

ments of  the  arms  in  the  act  of, 
847. 

—  mortises,  849,  882. 

-  oil    used    with     smooth    files,    for 

fibrous  metals,  852. 

—  originating  straight  edges  and  trial- 

plates,  or  planometers  by,  872. 

—  parallel  works,  879. 

—  pins  in  files,  removed  by  point  or 

scratch-brush,  853. 

-  planometer,  application  of,  in  filing 

flat  surfaces,  866  ;  comparison  of 
three,  876  ;  originating,  875. 

—  position  of  the  file  upon  the  work  in 

the  act  of,  847. 

—  position  of  the  individual  and  general 

movements  in,  large,  medium,  and 
small  works,  845. 

—  position  of  work  being  filed,  845. 

-  preparing  works   for,    by  chipping, 

pickling,  grinding,  &c.,  850. 

—  rebates  and  grooves,  881. 

—  rectangular  mortise  in  cylinder,  849. 

-  rectangulometer,   or    trial    bar,  for 

square  edges,  880. 

—  rectilinear  works,  878. 

-  rule  and  knuckle-joints,  893. 

-  scraper   and    scratch-brush   for   re- 

moving file-dust  and  pins,  853. 

-  scraping  flat  surfaces,  868  ;  import- 

ance of,  871. 

—  screen  for  light  in  scraping  surface 

plates,  876. 

—  small  works,  849,  861. 

—  snail-wheels  to  templets,  891. 

—  square  blocks,  879. 

—  square  holes,  883. 

-  straight  edges,  application  of,  865  ; 

originating,  875. 

-  surface  plates,  application  of,  866  ; 

originating,  875. 

-  swing  boards  and  tools  for  holding 

works  to  be  filed,  849. 

-  templets  for  arbitrary  forms,  890. 

-  thin  plates,  864. 

-  vice-bench,  855. 

flatting,    for    small    thin    works, 
864. 

—  hand,  for  very  small  works,  861. 


Filing  vice,  parallel,  advantages  of,  857. 

—  table,  for  small  works,  856. 

—  taper,  for  large  works,  854. 

—  tail,  for  ordinary  works,  855. 
wheels  to  templets,  891. 

Fincham,  John,  Esq.,  on  black  Botany  Bay 
wood,  75;  cowrie,  47;  dry  rot,  22  ;  ebony, 
84  ;  greenheart,  86  ;  iron  bark  wood,  29; 
larch,  19;  rock-elm  and  teak,  23;  ship- 
building woods,  65. 

Fires  for  forging,  general  management  of, 
204  ;  for  hardening  steel,  205,  241. 

Firs.     See  PINES,  100. 

Fish  skin  for  polishing  wood,  1060. 

Flanders-brick  for  founders'  cores,  336  ;  for 


polishing,  1061. 
lasks  for  b 


Flasks  for  brass-founding,  326  ;  iron-found- 

ing, 347;  three-part,  352. 
Flat  bit-tongs,  for  forging,  200. 
Flat  tool  for  turning  hard  wood  and  ivory, 

518  ;  brass,  521. 

Flattening,  principles  and  practice  of  flat- 
tening thin  plates  of  metal 
with  the  hammer,  414. 

—  sheet  metal  between  rollers,  399. 

—  thick  metal  works  with  the  hack- 

hammer, 247. 

Flexibility  of  wood  increased  artificially,  115. 
Flint,  analysis  of,  1029;  general  uses,  1061. 
Flints,  splitting  gun,  1  60. 
Floats  for  working  horn,  ivory,  and  tortoise- 

shell,  837. 
—      White's  perpetual  file,  with  moveable 

plates,  839. 

Fluids,  absorption  of,  by  timber,  114. 
Fluor  spar,  general  mode  of  working,  168; 

polishing,  1061. 

Fluxes  used  in  melting  metals,  309. 
Fly-presses  worked  by  hand,  934  ;  by  steam 

power,  936. 

Foggintor  granite  quarry,  170. 
Foils,  metallic,  for  jewellery,  1339. 
Forge,  for  large  works,  197;  for  ordinary 
works,    199;   portable,   for    small 
works,  202  ;  nailmakers',  231. 

—  air  blast  for,  198. 

—  bellows,  200,  202,  231. 

—  hardening  in,  241. 

—  melting  brass  in,  308. 

Forging,  iron  and  steel,  general  view  of,  1  95  ; 
ordinary  practice,  208. 

—  anchors,  198. 

—  angles,  or  corkings,  215. 

—  bent  works,  2  19. 

—  bolts,  213  ;  nuts  for,  216. 

—  chains  by  hand  and  machinery,226. 

—  chisels,  spades,  &c.,  228. 
cleavers,  shovels,  &c.,  199. 

—  collars  and  nuts,  216. 

—  complex  works,  217. 

—  conical  sockets,  223. 
corkings,  or  angles,  215. 

—  cranks  and  bent  works,  219. 


1433 


INDEX. VOL8.    I.    TO    III. 


Forging,  cutting  off,  with  the  chisel  in,  212. 
— .      Damascus  gun  barrels,  224. 

—  drawing-down  a  square  bar,  211; 

round  bolt,  213. 

—  fires,  general  management  of,  204. 

—  fuel  for,  204,  241. 

—  gun  barrels  by  hand  and  machinery, 

223. 

—  hatchet,  227. 

—  hearth  for  large  works,  197;    for 

ordinary  works,  1 99. 

—  heats   generally     employed,    206  ; 

«  taking  a  heat,"  207. 

—  hinges,  223. 

—  holes,  215. 

jumping  or  up-setting,  213. 

—  machine  for  spindles,  &c.,  461. 

—  mortises,  217. 

—  musket  barrels  by  hand   and  ma- 

chinery, 223. 

—  nuts  for  bolts,  216. 

—  paddle-shafts  for  large  steam-ships, 

196. 

—  platinum,  280. 

—  pliers,  234. 

—  railway    tires    and    wheels,   227 ; 

Bodmer's  patent  for,  1021. 

—  reducing,  or  drawing-down  by,  211, 

213. 

—  Rider's  machine  for,  spindles,  &c., 

461. 
rings,  226. 

—  round  bolts,  213  ;  large  shafts,  196. 

—  Russell's  patents    for'  iron    tubes, 

225,966,967,968. 

—  sand,  use  in  welding,  207. 

—  saws,  crown  and  riband,  1021. 

—  scissors,  233. 

—  scrap  iron,  manufacture  of,  197. 

—  screw  bolts,  three  methods  of,  213. 

—  setting  down,  or  making  shoulders, 

212. 

—  shafts  of  large  size,  195. 

—  shouldering  or  setting  down,  212. 

—  shovels,  cleavers,  &c.,  199. 

—  shutting.     See  WELDING. 

—  small  works,  202. 

—  sockets,  or  deep  holes,  216. 

—  spades,  chisels,  &c.,  229. 

—  square  works,  209. 
swaging,  431. 

—  tires   of    locomotive  wheels,   227  ; 

Bodmer's  patent,  1021. 
Forging  tools,  200 :— • 
Anvil,  203,  248, 
Bolster,  216. 
Bottom  tools,  232. 
Chisel,  212. 
Collar,  232. 
Crook  bit-tongs,  201. 
Drifts,  217,  233. 
Flat  bit-tongs,  200. 
Flatters,  208. 


Forging  tools  : — 

Fullers,  208,  212. 

Hammer,  monkey  used  for  anchors 
198  ;  Nasmy  th's  patent  direct  actioi 
steam  hammer,  958  ;  Oliver,  or  smal 
lift  hammer,  worked  by  the  foot 
962. 

Hammers,  application  of,  208;  hand 
210;  set, 208;  sledge,  199;  tilt,  199 

Heading  tools,  21 4,  231. 

Hook  wrench  or  set,  218. 

Hoop  tongs,  201. 

Mandrels  for  holes,  218. 

Pincer  and  plier  tongs,  201. 

Punches  for  red-hot  iron,  21 6, 233, 929 

Rounding,  232. 

Swage,  for  heads  of  bolts,  214  ;  block 
and  tools,  231 ;  spring,  233. 

Tongs,  200. 

Top  and  bottom,  232. 

Tribletfor  holes,  216. 
Forging,  tubes  for  gas,  &c.,  225, 963. 

—  twisted  gun-barrels,  224. 

—  upsetting  or  jumping  in,  2 1 3. 

—  Varley,  Mr.,  on,  234. 

welding,  general  examples  of,  219 
butt-joints,  221. 
chains  and  rings,  226. 
corner  joints,  222. 

—  hatchets,  228. 
heat,  207. 

—  hinges,  223. 
musket  barrels,  223. 

—  rings  and  chains,  226. 
sand,  use  of,  207. 

—  scarf  joints,  220. 
sockets,  223. 

—  steel  to  iron,  228. 
T  joints,  222. 

tires  for  railway  wheels,  227. 
tongue  or  split  joint,  221. 
tubes  for  gas,  &c.,  225,  963. 

—  uses  for  large  shafts,  196. 
Former  for  bending  tinned  plate,  389. 
Fossil  ivory,  138. 

Founding  and  casting,  317  to  375  : — 
Alloys  of  iron,  368. 
Arranging  patterns  in  moulds,  332. 
Back  mould,  339. 
Bells,  casting,  363. 
Berlin  castings,  974. 
Blast  for  melting  iron,  366. 
Blowing  of  metal  in  pouring,  317,  346 
Botting  iron  furnaces,  369. 
Breaking  down  large  cores,  373. 
Carrying  melted  brass,  344. 

—  melted  iron,  369. 
Casting,  general  remarks  on,  317. 

—  bells,  365. 
brass,  344. 

—  brass  ordnance,  364. 

—  figures,  solid  and  hollow,  319 


341. 


INDEX. VOL9.    I.    TO    III. 


1434 


Founding  and  casting  :— 
Casting  iron,  369. 

—  pewter  works,  320. 

—  screws,  Wilks's,  Warren's,  and 

Scott's  methods,  679. 

—  small  iron  chain,  374. 

—  specula,  371,  462. 

—  statues,  large,  hollow,  365. 

—  steam  cylinders,  373. 

—  stereotype,  325. 

—  tin  bearings  for  machinery,  322. 
type,  323. 

Charcoal,  to  prevent  oxidation  in  melt- 
ing, 309,  312,  316. 

Charge  for  iron  furnace,  367. 

Chilled  castings,  258,  349. 

Clichee  castings,  324. 

Clutches  used  in  loam  moulding,  360. 

Contraction  of  brass,  356;  of  iron,  355  ; 
of  metals  generally,  effects  of,  331, 
357 ;  contraction  rules  or  scales  for 
patterns,  355. 

Conversion  of  cast  iron  into  plumbago, 
368. 

Cooling  speculum  metal,  371. 

Cope  of  loam  moulds,  359. 

Copper  seldom  cast  pure,  345. 

Cores,  general  remarks  on,  330. 

—  annealing  for  figures,  342. 

—  annular,  for  pulley,  339. 

—  balance,  342. 

—  boxes,  336. 

—  burning,  337. 

—  drawback,  319. 

—  false,  338. 

—  Flanders-brick,  336. 

—  grains  for  supporting,  361. 

—  materials  for,  337. 

—  prints  for,  336. 

—  sand,  335. 

—  side  of,  350. 
Coring,  hollow  figures,  342. 

—  hollow  works,  330,  335. 
mortise  wheels,  351, 

—  panels,  351. 

—  pulleys  or  sheaves,  339. 

—  sand  moulds,  335. 
Cottles  in  pewterers'  moulds,  320. 
Crane  ladle  for  melted  iron,  369. 
Crucibles,  309. 

Cupola  for  melting  iron,  366. 
Different  qualities  of  cast-iron,  368. 
Drawback  or  false  core,  338. 
Drawing  air  from  castings,  371. 
Equality  of  thickness  in  castings,  357. 
Facings  for  foundry  moulds,  330,  340, 

343,  344,  348,  360. 
False  side  of  moulds,  334. 
Fine  castings,  340. 
Flasks  for  brass,  326;  iron,  347;  three 

part,  352;  filling  the  moulding  flasks, 

332. 
Fluxes  for,  309. 


Founding  and  casting  : — 

Founders'  lathe  for  turning  moulds,  362. 
Furnace,  air,  for  brass,  306. 

—  blast,  for  brass,  307;  for  iron, 

183,  366. 

—  botting  iron,  369. 

—  charge  for  iron,  367. 

—  cupola  for  iron,  366. 

—  fire,  management  of,  308. 

—  lead,  pewter,  &c.,  305. 

—  portable,  for  brass,  308,  973. 

—  refiners',  307. 

—  reverberatory,  for  brass,  307 ; 

for  iron,  367. 

—  tapping  iron,  369. 
Gaggers  used  by  iron  founders,  348 . 
Grains  for  supporting  cores,  362. 
Grunter  used  in  pouring  brass,  346. 
Iron,  general  remarks  on,  347. 

—  castings  hard  coat  of,  375. 

—  melting,  365. 

—  mixing  various  kinds  of,  368. 
Ladles  for  pouring,  369. 

Lathe  for  turning  cores  and  moulds,  362. 

Loam  moulding,  359. 

Loosening  bar,  333. 

Matrices  for  type,  324. 

Melting  brass,  &c.,  305  ;  iron,  365. 

Mixing  metals  for  brass,  345. 

—      various  kinds  of  iron,  368. 
Moulding,  principles  of,  318  ;  general 

outline   of    the   procees, 

326. 

—  bells,  363. 

—  Berlin  castings,  974. 

—  complex  works,  339. 

—  cored  works,  335. 
crooked  pipes,  362. 

—  delicate  objects,  343. 

—  elliptical  rods,  318. 

—  figures,  319,  341. 

—  fluted  columns,  356. 

—  frames,  351. 

— >         insects,  vegetables,  &c.,  343. 

—  loam  works,  359. 

—  mortise  wheels,  351. 

—  ordinary  works,  340. 

—  ordnance,  363. 

—  ornamental  works,  340, 363. 

—  pans  and  pipes,  362. 

—  pedestals  with  columns,  354. 

—  plain  bars,  326. 

—  reversing,  or  reverse  mould- 

ing, 339. 

—  runners  for  the  metal,  333, 

350,  353. 

—  sheaves  or  pulleys,  338. 

—  simple  works,  319. 

—  slide  rests,  352. 

—  statues,  365. 

—  steam  cylinders,  359. 

—  thin  ornaments,  339. 

to  written  measures,  355. 


INDEX. VOL8.    I.    TO     III. 


Founding  and  casting  : — 

Moulds,  general  remarks  on,  317. 

—  back,  for  reversing,  339. 

—  brick  dust  for  parting,  330. 

—  bullet,  320. 

—  closing  the,  334. 

—  clutches  for  loam,  360. 

—  cope  of  loam,  359. 

—  density  of,  331. 

—  dividing,  318. 

—  drag,  353. 

—  dry  sand,  349. 

—  drying,  330. 

—  earthen,  requred  to  be  porous. 

317. 
facings  of,  330  of,  344. 

—  false  side  of,  334. 

—  flasks  for  sand,  326. 

—  green  sand,  349. 

—  ingates  of,  333. 

—  iron,  for  chilled  casting,  349. 

—  loam,  for  brass  bells  and  guns, 

363;  for  iron  cylinders,  pans, 
pipes,  &c.,  359. 

—  materials  for  ordinary,  329. 

—  metal  moulds,  317  ;  for  pewter 

works,  320 ;  for  printing  types, 
323. 

—  nowel  of  loam,  359. 

—  odd  side  of,  334. 

—  opening  the,  333. 

—  partings  for,  330,  332,  340, 348, 

360. 

—  patterns  removing  from,  333. 

—  plaster  of  Paris,  325,  337,  341. 

—  repairing  the,  333. 
runner  stick,  353. 

—  sand,  326  ;  sand  for,  329,  348. 

—  shell  for  ordnance,  364. 
• —      stereotype,  325. 

—  stopping  off,  354. 

—  thickness  of  loam,  360. 

—  turning,  in  lathe,  360. 
Nasmy th's  crane  lathe,  370. 
Nowel  of  loam  moulds,  350. 
Odd  side  of  moulds,  334. 

Partings  for  foundry-moulds,  330,  332, 

340,  348,  360. 
Patterns,  general  remarks  on,  327,  355. 

—  arranging  in  moulds,  332. 

—  contraction,  rules  for,  355. 

—  correcting  imperfections    in, 

329. 

—  extracting  from  moulds,  333. 
filling  angles  of,  328. 

—  large,  358. 

lifting  handles  for,  329. 

—  loose  parts  of,  356. 

—  metal,  324. 

—  painting,  328. 

prints  for  cores,  336,  350. 

—  pulley  in  halves,  338. 

—  sy  metrical  form  desirable,35  7. 


Founding  and  casting  : — 
Patterns,  tapering,  327. 

—  thin  circular,  359. 

—  wax  models  for,  343. 

—  wheels,   Mr.  Dodd's  method 

of    arranging    the   spokes, 
358. 
wood  for,  327. 

Picker  out,  333. 

Pipes  for  water,  gas,  &c.,  362. 

Pouring     brass,   temperature    of    the 
metal,  334  ;  filling  the  moulds,  346 
pouring  bells,  guns,  and  statues,  364. 

Pouring   iron,    tapping    the    furnace, 
carrying   the    melted    metal,    369 
filling    the    moulds,    371  ;     pouring 
cylinders  and  heavy  castings,  373. 

Pressure  of  fluid  iron,  362. 

Pump  for  type  founding,  324. 

Runners,  333,  350,  353. 

Sand  for  moulds,  329,  348. 

Scoring  of  iron  castings,  361. 

Shank  for  pouring  iron,  369. 

Shuttle  for  pouring  iron,  371. 

Sow  for  large  castings,  37 1 . 

Steam  cylinders,  359. 

Stereotype,  325. 

Strickle  for  moulding  pipes,  363. 

Sullage,  or  scoria,  in  castings,  349. 

Tapping  iron  furnace,  369. 

Tedge  in  pewterers'  moulds,  321. 

Temperature  of  melted  brass,  344 ;  of 
iron,  369. 

Testing  the  quality  of  metal,  345. 

Thickness  of  castings   should   be  uni- 
form, 357. 

Thickness  in  loam  mouldings,  860. 

Three-part  flasks,  352. 

Tin  bearings  for  machinery,  322. 

Tools  for  foundry  work,  329. 

Trimming  iron  castings,  375. 

Turning  the  flasks,  332. 

Turning  moulds  for  pipes,  &c.,  360. 

Type,  323. 

Weight  of  iron  castings,  356. 

Wheels  with  wrought-iron  spokes,  358. 
Frame  saws,  724. 

Frames  for  panels  of  doors  and  billiards- 
tables,  57. 

—  glueing  up,  60. 

—  making  mortises  and  tenons  for,  7 15. 
Franklin's  expanding  center-bits  for  wood, 

1001. 
—         screw  bench-hook  for  joiners,  979. 

Freeman's  drill  tool,  1002. 

Freestones,  169;  smoothing,  1062;  saw- 
ing, 1189 

French  polish,  composition  of,  1392  ;  rub- 
bers for,  1090,  1414;  application  of, 
1415. 

French  screw  mandrel  lathe,  613. 

Furnace,  air,  for  brass-founding,  306  ;  iron- 
founding,  367;  large  forgings,  195. 


INDEX. VOrS.    I.    TO    III. 


I486 


Furnace,  blast,  for  brass,  307  ;  for  smelting 
iron  ore,  183;  dimensions  of, 
185  ;  air  used  in,  185  ;  iron- 
founders',  366. 

—  brass-founders',  306  ;  management 

of  the  fire,  &c.,  208. 

—  enamellers',  1059. 

—  Gill's  portable  blowpipe,  441. 
— •      iron-founders'  cupola,  366. 

portable,  for  brass,  &c.,  308,  973. 

—  puddling,  for  iron,  186. 

—  refiners',  307. 
reverberatory,  for  brass  founding, 

307;  iron  founding,  367;  forging  wrought- 

iron  tubes,  969. 
Fusee  engine,  old,  with  inclined  plane,  637  ; 

with   change   wheels   for  screw   cutting, 

617. 
Fustic-wood  (Morus  tinctoria),  85  ;    young 

fustic  (Rims  cotinus),  110. 

G. 

GAGE,  Birmingham  wire  and   sheet-metal, 
1013. 

—  bullet,  1017. 

—  filing,    for   bevilled   edges  of  metal 

works,  811. 

—  Hay  ward's  crown-glass,  1 020. 

-  joiners',  487  ;    bisecting,  488  ;  cut- 

ting, 487  ;  marking,  487  ;  applica- 
tion of,  501 ;  mortise,  488  j  router, 
488  ;  screw,  1014. 

-  Lancashire  wire,  1013. 

—  music  wire,  1014. 

—  needle  wire,  1014. 

-  rifle  and  fowling-piece,  1017. 

-  rod  iron,  1016. 

—  saw,  for  setting  out  fine  teeth,  692. 

-  sliding,  for  metal  works,  879,  1018. 
Gages  at  present  used   for  measuring  the 

thickness  of  sheet-metals  and  wire,  and 

proposals   for  a  new  system   of,  founded 

on  the  decimal  subdivision  of  the  standard 

inch,  1011. 

Saggers  used  by  iron-founders,  348. 
Salvanized  iron,  Craufurd's  patent  process, 

971  ;    Morewood    and   Rogers 's    patent 

galvanized  tinned  iron,  972. 
Gannister     stone,     for    polishing    cutlery, 

1062. 

Garnet  wrought  like  carnelian,  1062. 
Gaulthier's  table  of  the   melting  heats  of 

alloys  of  lead,  435. 
Gelatine  in  bones  and  shells,  118. 
Gem  engravers,  English,  Mr.  H.  Weigall  on 

their  comparative  abilities,  1362. 
Gem  engraving,  general  remarks,  1348. 

-  bench,  engine,  and  tools,  1349. 

-  cameo-cutting,  1365;  adaptation  of  the 

design  to  the  stone,  1367;  applica- 
tion of  the  term  onyx,  1366  ;  spade 
for  smoothing,  1368. 


Gem   engraving,    charging   the   tools   with 
diamond  powder,  1 354. 

—  cutting  flat  surfaces  and  curved  lines, 

1360. 

—  diamond  powder,  preparation  of,  1 052. 

—  difficulties  of  manipulation,  1361. 

—  polishing  engraved  surfaces,  1362. 

—  position  of  the  hands  in,  1358;  of  the 

stone,  1361. 

—  qualities     of     different     stones     for, 

1363. 

—  stippling,  1360. 

—  tools,  ^construction  of,    1351;    succes- 

sion of,  1357. 

—  wax  or  clay  for  taking  impressions  in, 

1357. 

Gems,  fictitious,  1338. 

Geneva  facetting  instrument,  1337. 

—      polishing   tool  for  heads  of  small 
screws,  1185. 

Geometrical  solids,  Cowley's  scheme  for 
cutting  models  of,  in  paper,  384. 

Geometrical  solids  in  wood,  general  re- 
marks on  their  production,  779 ;  cut 
with  the  circular  saw,  769  ;  from  prisms, 
774. 

German  boring-bit  for  wood,  544. 

—  hone  for  razors,  1062,  1066. 

—  plough  for  wood,  486. 

—  rimer  for  wood,  486. 

—  silver,  composition  of,  279. 

—  steel,  manufacture  and  qualities  of, 

192. 

—  treatises  on  turning,  &c.,  6. 
Gibbs's  patent  carving-machine,  1025. 
Gilding  metal,  composition  of,  268. 

Gill,  Mr.,  drill-stock  for  small  drills,  555  ; 
portable  blowpipe  furnace,  441  ;  harden- 
ing composition  for  steel,  249. 

Gimlet,  common,  541;  twisted,  543. 

Glass,  ancient  Egyptian  mosaics  in,  767. 

—  annealing,  237;  lengthens  in  process, 

138. 

—  blowpipes  for  toys  in,  440. 

—  compared  with  steel,  237. 

—  crown,  Haward's  gage  for,  1020. 

—  cutters'   wheel,  1297;  stones,  1299; 

polishing  wheels,  1118. 

—  cutting,  glaziers'  diamond  for,  176. 

—  cutting,  1296  ;  rough  grinding,  1298; 

smooth  grinding,  1299  ;  polishing, 
1300. 

—  drops  for  chandeliers,  grinding  and 

polishing,  1301;  pinching,  1298. 

—  flutes,    1298  ;    pillars    and    splits, 

1299. 

—  screws     on     smelling-bottles,    &c., 

614  ;    stoppers   for  bottles,  &c., 
1300. 

—  disks  for  sextants,  grinding,  1 228. 

—  engraving,  general  remarks  on,  1348  ; 

engine  or  tool,  1369  ;  wheel,  1371 ; 
routine  of  the  process,  1 372. 


14.37 


INDEX. VOLS.    I.    TO    III. 


Glass  lenses,  grinding  by  hand,  1262 ; 
smoothing  or  trueing,  1266;  polish- 
ing, 1267;  machinery  for  grinding 
and  polishing,  1269,  1292;  micro- 
scope, grinding  and  polishing, 
1273;  object  glasses,  1270;  Ross's 
sphereometer,  1271. 

—  paper,  1062. 

—  plate,  manufacture  of,  1217;  casting, 

1218;  grinding,  rough,  by  ma- 
chinery, 1219;  smooth,  by  hand, 
1220 ;  polishing,  by  hand,  1223  ;  by 
machinery,  1221. 

—  polishing,  general  routine,  1062. 

—  sheet,  manufacture  of,  1223;  grinding 

machines,    1224  ;    polishing    ma- 
chines, 1225. 

—  spheres,  1257. 

—  spherical  surfaces,  1262. 

Glazers,   or    glazing-wheels,  for    polishing 

cutlery,  &c.,  1063,  1118. 
Glaziers'  diamond,  for  cutting  glass,  176. 

—  vice,  for  drawing  window  lead,  428. 
Globes,  covering  with  paper,  379. 

Glue,  preparation  of,  58  ;  white  fish,  154. 
Glueing  various  works  in  wood,  57. 

—  boards,edges  of,  59 ;  wide  boards,  51 . 

—  curved  works,  with  cauls,  62. 

—  dovetailed  box,  59. 

—  frames  for  panels,  60. 

—  mosaic  works,  763. 

—  mouldings,  59. 

—  thin  circular  patterns  for  founding, 

359. 

—  turned  works,  58. 

—  veneers,  61. 

Gold,  general  characters  and  uses,  malle- 
ability and  ductility  of,  273;  cohe- 
sive force  of,  288. 

—  alloys,  274  ;  cohesive  force  of,  289  ; 

malleability  of,  296. 

—  antique,  blue,  green,  grey,   and  red, 

composition  of,  276. 

—  facetting  works  in,  1184. 

—  polishing,  1063,  1185. 

—  standard,  spring,  and  jewellers',  com- 
position of,  275. 

Gooch,  Mr.  D.,  hardened  steel  tires  for  wheels 

of  locomotive  engines,  257. 
Gouge  for   turning   wood,    512;   grinding, 

1139  ;  sharpening,  1145. 
Gouge  bits,  for  boring  wood,  539. 
Grandjean's  screw-cutting  lathe,  616. 
Granite,  169;  quarrying,  170;  working,  171. 
Graver    for   turning   iron   or    steel,   523 ; 

grinding,  1140. 
Green  ebony  wood,  85. 
Greene,  Dr.  R.,  machine  for  grinding  and 

polishing  lenses  and  specula,  1292. 
Greener,  Mr.,  on  Damascus  gun  barrels,  224. 
Greenheart-wood  (Laurus  chlorozylori),  85. 
Greenstone.    See  HONES,  1064. 
Grenadillo-wood,  85. 


Grey  polishing  stone,  1066. 

Grinders,  conical,  for  axletree  boxes,  1254  j 
bead  tools  and  drills,  1170;  draw- 
plates,  423  ;  lathe  collars,  1256 ; 
mandrels,  1252;  spheres,  1259; 
stoppers  of  glass  bottles,  1301. 

—  cylindrical,    for    ordinary    holes, 

1245  ;  parallel  holes,  1246;  short 
holes,  1248  ;  rods,  1233  ;  works 
requiring  accuracy,  1237. 

—  expanding,  for  cylindrical  holes, 

1247. 

—  fixed,  for   conical   works,  1253  ; 

for  cylindrical  works,  1237. 

—  flat,   for  cast-iron   works,    1074, 

1089  ;  disks  for  sextants,  1227; 
marble  works,  1 089, 1196;  plane 
specula,  1231  ;  small  steel  and 
watch  work,  1075,  1180,  1185. 

—  revolving,  for  conical  and  cylin- 

drical works,  1237,  1242,  1244  ; 
flat  works,  1113,  1180. 

—  spring,   for  conical  holes,  1254  ; 

mandrels,  1252;  cylindrical  holes, 
1248. 

—  spherical, for  lenses,! 296  ;  specula, 
1275. 

Grinding,  general  and  preliminary  observa- 
tions on  grinding  and  polishing, 
1027;  DESCRIPTIVE  CATALOGUE  , 
of  the  Apparatus,  Materials, 
and  Processes,  commonly  em- 
ployed in  the  Mechanical  and 
Useful  Arts,  1033. 

—  alabaster  and  other   soft   stones, 

1034. 

—  angular  tools   for  eccentric   and 

ornamental  turning,   1 1 64. 

—  axle-tree  boxes,  1254. 

—  bead  tools  and  drills,  1170. 

—  Cadrans,  or  Geneva,  instrument 

for,  facets,  1337. 

—  carnelian,  and    stones  of  similar 

hardness,  1044. 

—  chisels,  1138. 

—  collars  for  lathe  mandrels,  conical, 

1255  ;  cylindrical,  1246. 

—  concave    works   with   the  grind-  ' 

stone,     1111  ;      with     artificial 
grinders,  1170. 

—  conical  holes,   1254  ;  collars  for 

lathe  mandrels,  1255. 

—  conical  surfaces,  1251 ;  glass  stop- 

pers for  bottles,   1301  ;   lathe 
mandrels,  1253. 

—  convex  works,  on  the  grindstone, 

1111;    on   the  horizontal  lap, 
1316. 
Grinding  cutlery,   general  routine  of   the 

process  in   common  and  fine 

works,  1051. 

blades  of  table-knives,  1110. 
convex  works,  1111. 


INDEX. VOLS.    I.    TO    III. 


1438 


Grinding  cutlery,   position  of  the   grinder 

when  at  work,  1106. 

Grinding  cutting  tools,  on  the  grindstone, 
general  remarks,  1133. 

chisels  and  gouges,  1 138. 

drills,  1140. 

guides  for  grinding  ordinary 
turning  tools  to  definite 
angles,  1158. 

instrument  for  slide-rest  tools 
for  ornamental  turning,  1 1 64. 

artificial/grinders  for,  1156. 

plane  irons,  1 1 36. 

slide-rest  and  screw  tools,  &c., 
1141. 

tools  with  concave  edges,  1 170. 

turning  tools  used  in  the  hand, 
1139. 

vertical  lap  for,  1169. 

Grinding  cylindrical  surfaces,  general  re- 
marks, 1232. 

accurate  works,  1236. 

collars  for  lathes,  1246. 

fitting  internal  and  external 
cylinders  by,  1249. 

holes,  1245. 

lathe  mandrels,  1237. 

rims  of  pulleys,  Messrs.  Ran- 
dolph, Elliot,  &  Co.'s  machine 
for,  1244;  Mr.  J.  Whitelaw's 
machine  for,  1242. 

ring  gages,  1249. 

rods  by  hand,  1235;  in  the 
lathe,  1234. 

rollers,  common,  1236. 

rollers  for  paper-making,  finish- 
ed with  water  only,  1237. 
Grinding  disks  for  sextants,  1228. 

drills,  pointed,  1140;  bead,  1171; 

moulding,  1173. 

—  dry,   1111  ;  various  contrivances 

to  obviate  the  unhealthiness  of 
the  practice,  1112. 
Grinding  facets,on  gold  and  silver  works,!  184. 

—  lapidaries'    works,  1045,    1306, 

1321,  1327, 1343. 
steel  jewellery,  1182. 
Grinding  flat  surfaces.  See  PLANE  SURFACES. 
flat  tools  for  turning  wood,  ivory, 

and  brass,  1139. 
Grinding,  glass  cutting,  1296. 

drops  for  chandeliers,  1301. 
plate  glass,  1219. 
sheet  glass,  1224. 
stoppers  for  bottles,  1301. 
Grinding    gouges,  1138. 

granite,  172,  1063. 

gravers,  1140. 

guides  for,  tools  to  definite  angles, 

1158. 

hack-hammer,  1109. 
heavy  plates,  1110. 
heel  tools,  1140. 


Grinding,  holding  small  works  while,  1111. 

—  holes,  conical,  1254  ;  cylindrical, 

1245  ;  drawplate,  423. 
~-         horizontal,  machine   for   cutting 

tools,  1157. 

Grinding,  instrument  for,  and  setting  ordi- 
nary turning-tools  with  reti- 
linear  edges,  1159. 

—  instrument      for,      and     setting 

straight  and  angular  tools  for 
ornamental  turning,  1164. 
instrument,    for    cutting    facets, 
amateur,  1343;  Geneva,  1337. 

—  lapidaries'  work,  1 302, 1 3 1 4, 1 32 1 . 

See  also  ALABASTER,  1033  ; 
CARNELIAN,  1044 ;  and  SAP- 
PHIRE, 1091. 

—  lapping  flat  works  in  metal,  1 180. 

—  laps  or  metal  wheels  for,  1113; 

horizontal,  1 157 ;  vertical,  1169. 

—  lathes,  1105,  1131. 

—  left-side  tools,  1139. 

—  lenses  by  hand,  1050,  1262, 1266; 

machinery  for,  1269,  1292  ;  mi- 
croscope, 1273;  object  glasses, 
1270. 

Grinding  machines  for  cylindrical  rims  of 
pulleys,  Messrs.  Randolph,  El- 
liot, &  Co.'s,  1244  ;  Mr.  J. 
Whitelaw's,  1242. 

—  machines  for  flat  surfaces,  marble 

slabs,  Mr.  Tulloch's,  1211. 
marble  mouldings,  1214. 
metal  cutting  tools,  1 156. 
metallic  surfaces,  Mr.  J.  Nas- 

myth's,  1187. 
plate-glass,  1219. 
sheet-glass,  1224. 

—  machines   for    specula,    Dr.    R. 

Greene's,  1292;  Rev. W.Hodg- 
son's, 1293;  Mr.  W.  Lassell's, 
1289  ;  Earl  Rosse's,  1280; 
Mr.  C.  Varley's  lathe,  1269. 

—  machines  for  spherical  surfaces, 

lenses,  1269,  1292. 

marbles  for  children,  1078. 

rounded  rims  of  pulleys,  Mr.  J. 
Whitelaw's,  1244. 

spheres,  Mr.  H.  Guy's,  1257. 

stoppers  of  earthenware  jars, 

1295. 

Grinding   marble  works,  general   remarks 
on,  1076,  1190. 

flat  surfaces  by  hand,  1 1 96  ;  by 
machinery,  1210. 

mouldings,  circular,  1215;  rec- 
tilinear, 1214. 

—  sawing  by  hand,  1191 ;  by  ma- 

chinery, 1202. 

Grinding  massive  works,  as  anvils  and 
heavy  plates,  1110. 

—  materials,     analysis    of,     1029  ; 

catalogue  of,  1033. 


1439 


INDEX. VOLS.    I.    TO    III. 


Grinding  moulding-tools,  1141,  1176. 

—  Nasmyth's  machine  for,  flat  sur- 

faces on  large  metal  works,!  187. 

—  object  glasses  for  telescopes,  1270. 

—  optical   glasses    by   hand,    1050, 

1228,    1262  ;     by    machinery, 
1269,  1273,  1292. 

—  parallel  disks  for  sextants,  1230. 

—  plane-irons,  bench,    496,    1136; 

moulding,  1138. 

—  plane  surfaces  in  glass,  1219,1224, 

1227. 

Grinding  plane  surfaces,  lapidary  works, 
1307,  1314,  1321. 

—  marble,  1196,  1210. 
metal,  871,  1180,  1227. 

Grinding  planing  tools  for  brass  and  iron, 
530,  1141. 

—  plate-glass  by  hand,    1221  ;   by 

machinery,  1219. 

—  point  tools,  1140. 
. —         porphyry,  171. 

—  position  of  the  grinder  when  at 

work,  1106. 

—  razors,  1051,1147. 

—  right-side  tools,  1139. 

—  rollers      accurate,      for      paper- 

making,  1237  ;  ordinary,  1236. 
round  tools,  1140. 

—  saws,   1110  ;  large  veneer,  815  ; 

teeth  of  circular,  1011. 

—  screw  tools,  1141. 

—  slide-rest  tools  for  plain  turning, 

528,  983,  1141;  for  ornamental 
turning,  1164. 

—  small  works,  1111. 

Grinding  specula,  for  reflecting  telescopes, 
general  remarks  on,  1274, 
1288. 

—  backs    for    supporting,     1275, 

1288. 

bed  of  hones  for  smoothing, 
1276  ;  difficulties  of  the  pro- 
cess, 1280. 

—  Edwards,  Rev.  J.,  grinder  and 

polisher  for,  1276. 

—  Greene,  Dr.  Rv  machine  for, 

1293. 

Hodgson,  Rev.  W.,  machine  for 
small,  1293. 

—  Lassell,  Mr.  W.,  machine  for 

medium  size,  1289. 

—  Rosse,   Earl   of,   machine   for 

large,  1280, 1286. 
with  plane  surfaces,  1'231. 
Grinding  spheres,    Mr.    Guy's   method    of 
producing  accurate,  1257. 

—  marbles  for  children,  1078. 
Grinding    spherical       surfaces,       lapidary 

works,  1316. 

lenses  by  hand,  1050,  1262, 
1266  ;  by  machinery,  1269, 
1292. 


Grinding  spherical  rounded  rims  of  pulleys, 
Mr.  J.  Whitelaw's  machine, 
1244. 

—  stoppers  for  earthenware  jars, 

1293. 
tools  for  lenses,  &c.,  1263. 

—  square  tools  for  brass,  1 1 40. 

—  tongs,  for   holding  small  works, 

1111. 

—  triangular  tools,  1140. 

—  turning  tools,  on  artificial  ginnders, 

1158,    1170  ;  on   the  ordinary 

grindstone,  1138. 
watch-springs,  250. 

Grindstones,  or  Gritstones,  of  various  kinds, 
viz.,  Bilston,  Newcastle, 
Sheffield,  and  Wickersley  ; 
Sheffield  bluestone,  carpen? 
ters'  rubstone,  Devonshire 
batts,  Yorkshire  and  Congle- 
ton  grits,  1064;  general  re- 
marks on  using,  1 109. 

adaptation  to  the  forms  of 
works,  1111. 

cutlers',  driven  by  fly-wheel, 
1105. 

—  dolly  bar  for  adjusting  the  height 

of  water  in  troughs  of,  1133. 

driven  by  steam-power,  for 
heavy  edged-tools,  saws,  gun 
barrels,  &c.,  1106. 

driven  by  treadles  and  winch- 
handles,  for  ordinary  tools, 

1104,  1128. 

driven  by  foot  and  fly-wheels, 
for  small  tools  and  cutlery, 

1105,  1131. 
dry  and  wet,  1111. 
engineers',  for  tools,  1107. 
fixing  large,  on  their  spindles, 

1108. 

fixing  small,  1131. 
• —  flanges  and  rings  for,  to  prevent 

the    stones    from   breaking, 

1107. 

frames  for,  1104,  1128. 
grinding   face  of  glass-cutters, 

1299. 
hacking,  1065,  1108.  - 

—  horse  or  seat  at,  for  grinder,  106. 
mounting,  various  methods  of, 

1104,  1128. 

—  preservation  of  the  surface  of, 

1134. 

primitive,  1128. 
ragging  or  straggling,  1109. 
• —  rovingandturningsmooth,1109. 

spindles  for,  1104. 
splitting,  1106. 

—  turning,   1108. 

—  velocity  of,  1107. 

—  water-trough  for,  1104. 

—  wet  and  dry  stones,  1111. 


INDEX. VOLS.    I.    TO    III. 


1440 


Grooves,  filing,  and  rebates,  angular  and 
square,  881  ;  semicircular,-  886. 

Grooving- planes,  484. 

Grunter  used  in  iron-founding,  346. 

Gums,  amber,  anime,  copal,  damar,  lac, 
mastic,  and  sandarac,  respective  qualities 
of,  as  bases  for  varnishes,  1374 — 1376. 

Gums  and  resins  in  woods,  30. 

Gum-wood  (Eucalyptus),  86. 

Gun  barrels,  manufacture  of,  by  hand  and 
machinery,  223  ;  broaches  for,  575. 

—  boring  large,  576. 

—  casting  large,  363. 

—  locks,   case-hardening    and   tempering 

springs  of,  250. 

—  metal, composition  of,  &c.,  270,272,273; 

ill  effects  of  cooling,  too  rapidly,  295. 

—  punch,  for  wadding,  927. 

Guy,  Mr.  H.,  method  of  producing  accurate 

spheres  by  grinding,  1257. 
Gypsum.     See  ALABASTER,  1033. 

H. 

HACKING, grindstones,  11 08;  laps,  1044, 1065. 
Hackmetack  larah.     See  PINES,  100. 
Hamilton,  Mr.  S.,  patent  machinery  for  saw- 
ing   bevilled    and   curvilinear   works  in 
wood,  805. 
Hammer,  application  of,  in  forging,  208. 

covered  with  cloth  for  sheet-metal 

works,  411. 

hack,  for  flattening  thick  metal 
works,  247  ;  for  dressing  grind- 
stones, 1109. 
helve,  for  manufacture  of  wrought- 

iron,  186. 
monkey  or  vertical,  for  anchors, 

&c.,  198. 
Nasmyth's    patent    direct   action 

steam,  958. 
Oliver,  or  small   lift,  worked  by 

the  foot,  962. 

raising,  for  sheet-metals,  403. 
smiths'     hand,    210  ;    set,    208 ; 
sledge,  199. 

—  tilt,  for  steel,  193  ;  for  large  forg- 

ings,  199. 
tongs,  201. 

—  veneering,  63. 

iammering,  flattening  thin  plates  of  metal 

by,  414. 
hardening  steel  by,  235. 

—  iron,  Mr.  James  Nasmyth's  ex- 

periments on  effect  of,  461  ; 
Mr.  C.  Varley  on,  234. 
saws,  flattening  by,  414;  setting 
saw-teeth  by,  696. 

—  sheet-metal    works,   effects   of 

hollow  and  solid  blows  in, 
399;  peculiarities  of  the  tools, 
386,  410;  raising,  398;  snarl- 
ing. 412. 


Hammering,  steel   to  improve   its   quality, 

194;  hardening  by,  235. 
Handrail  plane,  475. 
Hand-saws,  708  ;  sharpening,  694. 
Hand-vices,  861. 

Hanging  tools  for  turning  iron,  526. 
Hardening,  general  view  of  the  subject,  235 ; 

analysis  of  steel  andiron,  236. 
- —         alternately  with   soft  portions, 

243. 

—  anvils,  large  dies,  &c.,  248. 
axletrees,  253. 

—  case-hardening  cast  and  wrought 

iron,  260 ;  alternately  with  soft 
portions,  261;  compared  with 
cementation  of  steel,  263  ; 
gun-locks  and  snuffers,  261  ; 
steel,  254  ;  with  prussiate  of 
potash,  262. 

—  composition  used  for  saws  and 

springs,  249. 

—  cooling,    modes   of,   242,   248  ; 

quickly  or  slowly,  238. 

—  cracks  in,  risk  of    occurrence, 

244;  Stodart's  remarks  on  the 
causes  of,  252. 

—  cutting  tools,  245. 

—  dies,  248,  255. 

—  distortions  in,  risk  of  occurrence, 

244;  attempts  to  prevent,  254; 
Dr.  Wollaston's  and  Mr. 
Perkins's  method,  256;  cor- 
rected with  the  hack-hammer, 
247. 

—  files,  253. 

—  fire  for,  205. 

—  fuel  for,  241. 

—  Gooch's    steeled    railway  tires, 

257. 

—  hammer,  235. 

—  hatchets,  adzes,  &c,  248. 

—  heating,  general  modes  of,  240. 

—  limited  in  range  without  temper- 

ing, 24*. 

—  oxidation  in,  Mr.  Oldham's  me- 

thod of  preventing,  255;  Sir  J. 
Robison's  workshop  blowpipe, 
970. 

—  penknives,  248. 

—  razors,  248,  252. 

—  saws,  249. 

—  small  drills,  &c.,  247. 

—  springs,  249. 

—  steel,  analysis  of,  236  ;  compari- 

son with  glass,  237. 

—  steel  balls,  1260;  pens,  249. 

—  steel  plates  for  transfer  engrav- 

ing, 254. 

—  thick  works,  244. 

—  thin  work,  245. 

watch-springs,  250. 

Hardman,  H.,  Esq.,  on  Cam-wood,  45. 
Hardwood  lacker,  1392. 


14'U 


INDEX. VOLS.    I.    TO    III. 


Hare,  Dr.,  method  of  bleaching  lac  varnish 

1393. 

Hare- wood.     See  SYCAMORE,  107. 
Hartman     Schopperum's    engraving   of    a 

grinder,  1129. 
Harvey,    Mr.  F.  E.,    patent    for    forging 

wrought  iron  tubes,  967. 
Harvey,  Mr.,   patent    curvilinear  recipro- 
cating saws,  1022. 

Harvey  &  Co.,  very  small  cast-iron  chain,  374. 
Hassenfratz  on  sawing  thick  logs  of  timber 

with  two  circular  saws,  785. 
Hatchet,    action    of,  472 ;   forging,    227 ; 

hardening,  248. 

Hawthorn  wood  (Cratcegus  oxyacaniha),  86. 
Hayward,  Mr.,  gage  for  thickness  of  crown 

glass,  1020. 

Hazel-wood  (Oorylus  Avellana),  86. 
Healey,  Mr.,  screw-cutting  apparatus,  618. 
Heats,  for  forging,  206. 

—    for  tempering  steel,  245. 
Heel  tools,  for  turning  iron,  525  ;  grinding, 

1140. 

Heliotrope.     See  BLOODSTONE,  1037. 
Helve-hammer,  for  manufacturing  wrought 

iron,  186. 
Henning,  Mr.,    slate  moulds  engraved  in 

intaglio  by,  166. 

Hermstadt,  Dr.,  imitation  gold,  276. 
Hexahedron,  model  of,  cut  with    circular 

saws,  774. 
Heyne,    Dr.,    composition   of    metal     for 

Biddery  ware,  286. 

Hick,  Mr.,  experiments  on  the    force  re- 
quired for  punching  iron,  952  ;   sawing 

machine  for  planks,  744. 
Hickory-wood  (Juglans  alba),  86. 
Hilton,  Mr.,  rimer  for  wine  coopers,  573. 
Hindley,  Mr.,  curved  tangent  screw,  592. 
Hinge-joints  formed  with  files  and  cutters, 

894. 

Hippopotamus  teeth  or  ivory,  138. 
Hodgson,  Rev.  W.,  apparatus  for  grinding 

and  polishing  small  «specula,  1293. 
Holdfasts  for  planing  benches,  495. 
Hollingrake's    patent    for    casting    metals 

under  pressure,  345. 
Hollow  fires  used  in  forging,  204. 
Hollows  and  rounds,  492. 
Holly-wood  (Ilex  cequifolium),  86. 
Holtzapffel's    boring-bit,    with    changeable 

cutters,  1006. 
cutter-bar,  for  iron,  535. 
cutter-bar  for  square  thread 

screws,  631. 
new  system  of  scales  of  equal 

parts,  356. 
regulating  dies  for  plug  taps, 

676. 
screw    threads,   approximate 

measures  of,  673. 
Honduras  mahogany  (Swietenia  Makogoni), 

92. 


Hone,  bed  of,  for  smoothing  specula,  1276. 

—  Fayrer's  swing,  1060. 

—  slates  of  various  kinds  for  sharpening 

and  polishing,  viz. — Norway  rag- 
stone,  Charnley-forest  stone,  Ayr- 
stone,  Scotch-stone  or  snake-stone, 
Idwall  or  Welsh  oilstone,  Devon- 
shire oilstone,  cutlers'  green, 
German  razor,  blue  polishing 
stone,  grey  polishing-stone,  Welsh 
clearing-stone,  Peruvian,  Welsh, 
white  and  black  oilstone,  Arkan- 
sas stone,  Bohemian  stone,  1065 
—1067. 

—  Turkey,  1081;  analysis  of,  1029. 
Hood,  Mr.  C.,  on  changes  in  the  structure 

of  iron,  460. 
Hook  for  planing-bench,  494. 

—  Mr.  Franklin's  screw  bench,  979. 

—  tools,  for  turning   iron,   525  ;    soft 
wood,  514. 

Hoop  tongs,  for  forging,  201. 

Hopkinson   and  Cope,  Messrs.,  method  of 

grinding  accurate  cylindrical  rollers  for 

paper-making,  1238. 

Horn,  antelope,  buffalo,  chamois,  ox,  stag, 
and  rhinoceros,  121. 

—  Chinese  sensitive  leaves,  123. 

—  Deakin's  patent  for  working,  126. 

—  drinking,  manufacture  of,  123. 

—  dyeing,in  imitation  of  tortoiseshell,!  26. 

—  elasticity  of,  124. 

—  joining,  126. 

—  moulding,  125. 

—  opening  ox,  123. 

—  polishing  handles  made  of,  1067. 

—  separating  the  core  from,  122. 

—  softening,  123,  126. 

—  splitting  into  leaves,  123. 

• —     straightening  buck  and  stag,  957. 
Huntsman,  Mr.,  manufacture  of  steel,  192. 
Hyacinth  or  jacinth.     See  ZIRCON,  1126. 
Hydraulic  machine  for  cutting  off  copper 
bolts,  924. 


1. 


ICOSAHEDRON  cut  with  the  circular  saw,  776. 
Icositesserahedron    cut    with    the  circular 

saw,  777. 

Idwall,  or  Welsh  oilstone,  1065. 
Indian  blackwood  (Dalbcrgia  lati folia).  See 
EAST  INDIAN  BLACKWOOD,  83. 

—  lapidaries'  corundum  wheels,  1049. 

—  level,  555. 

—  varnishes,  1417. 
Inlaying  buhl  works,  732. 

—  handles  of  cutlery,  135. 

—  marble  works,  1 G  7 ;  general  method 

of  proceeding,  1201. 

—  marquetry  works,  738. 

—  saws,  732  ;  setting  out  and  sharpen- 

ing the  teeth,  692. 


INDEX. VOLS.    I.    TO    III. 


1442 


Inside  turning  tools,  for  hard  woods,  520; 

for  soft  woods,  514,  516. 
Instrument  for  grinding  facets,  1343. 

—  for  grinding  and  setting  ordinary 

turning  tools  with  rectilinear 
edges,  1159. 

—  for  grinding  and  setting  straight 

and  angular   tools   for   orna- 
mental turning,  1164. 

—  for  setting  bead  tools  and  bead 

drills,  1172. 

—  for  setting  straight  and  angular 

tools  for  rose-engine  turning, 
1162. 

Iridescence  of  pearl  shell,  119. 
Iron  : — 

Analysis  of,  236. 

Cast,  manufacture  of,  182. 

—  alloys  of,  368. 

—  blast  furnaces  for  smelting,  183. 
Cast,  chilled  castings,  349. 

—  cohesive  force  of,  287. 

—  conversion  into  plumbago,  368. 

—  experiment  on  manufacture,  by 

Mr.  Mushet,  185. 

—  fluxes  used  in  smelting,  184. 

—  hardening,  260. 

—  malleable  iron  castings,  259;  case- 

hardening,  261. 

—  mixing  various  kinds  of,  368. 

—  polishing,  1046. 

-     qualities  of,  185. 

—  roasting  ore,   182. 

—  smelting  ore,  183. 
Cement  for  joints  of,  454. 
Cold-short,  189,  460. 
Forging.     See  FORGING. 
Founding.     See  FOUNDING. 
Furnace  for  smelting,!  83 ;  for  founding, 

366,  367. 

—  charging  smelting,  183. 

—  dimensions  of  smelting,  185. 

—  puddling,  186. 
Galvanized,  Craufurd's  patent  process, 

971;  Morewood  and  Rogers'  patent 

tinned,  972. 
Pyrolignite    of,    used   for    preserving 

timber,  114. 
Red-short,  189,  460. 
Wrought,  manufacture  of,  186;  Clay's 
patent  process,  958. 

—  charcoal,  187. 

—  cohesive  force  of,  287. 

—  cold  hammering,  effects  of, 

460. 

—  cold-short,  189,  460. 

—  Damascus,  for  gun-barrels, 

224. 

—  fracture,  index  of  quality  of, 

ICO. 

—  polishing,  186. 

—  puddling  and  rolling,  186. 

—  qualities  of,  189. 
VOL.  in. 


Iron  — 

Wrought,  red-short,  189,  460. 

—  refining,  186. 

—  rolls  for  rails,  &c.,  187. 

—  shingling,  186. 

—  structure  and  tenacity  influ- 

enced   by    treatment    of, 
234,  460. 

—  toughness  of,  189. 

—  tubes,  manufacture  of,  225, 

963. 

—  varieties  of,  189. 

—  Varley's  remarks  on,  234. 
Iron- wood,  87. 

Irving,    Mr.,    patent  machine   for  carving 

wood,  954. 

Isinglass  cement  or  glue,  155,  957. 
Ivory,  composition  of,  118  ;   general   cha- 
racters of,  137. 

—  African  and  Asiatic  varieties  of,  1 38, 

141,  144. 

—  ancient  statues  of,  140. 

—  billiard  balls,  shrinkage  of,  152. 

—  bleaching,  153, 

—  bullets  found  in,  145. 

—  carving,  140;  Mr.  Franchi's  mode  of 

imitating,  with  plaster  casts,  1085. 

—  cement,  154,  957. 

—  centering  blocks  of,  in  the  lathe,  149. 

—  choice  of,  in  the  tusk,  144. 

—  chucking  rough  blocks  of,  149. 

—  colours  of  tusks  of,  142. 

—  contraction  of,  152. 

—  curvature  of  tusks  of,  142. 

—  cutting  out  rings  of,  151. 

—  cutting  up  tusks  of,  for  rectangular 

works,  146 ;  for  turning  works,  148. 

—  destruction  of  elephants  for,  141. 

—  difficult  to  match  for  colour,  grain, 

&c.,152. 

—  durability  of,  140. 

—  enamel  of  hippopotamus,  139. 

—  external  appearance  of  tusks  of,  142. 

—  factitious,  1 55. 

—  floats  for  carving,  838. 

—  fossil  teeth,  138. 

—  grinders  of  the  elephant,  1 39 ;  of  the 

hippopotamus,  138;  of  the  mam- 
moth, 138. 

—  miniature  leaves,  cutting  with  circu- 

lar saws,  808. 

—  narwal  teeth,  139. 

—  nuts,  112. 

—  opaque,  142,  144. 

—  polishing,  carved,  filed,  and  turned 

works,  plain  and  ornamented, 
1067,  1122. 

—  preparation  of,  146. 

—  saw  for  cutting  up  tusks  of,  146, 728. 

—  sawing,  handles  from  tusks  of,  147; 

keys  for  pianofortes,  148 ;  rect^ 
angular  works,  146;  turnery  works, 
148. 

B-fl 


1443 


INDEX. VOLS.    I.    TO    III. 


Ivory,  scales  subject  to  contraction,  152. 

—  sea-cow  teeth,  139. 

—  seasoning,  152. 

—  sections  of  tusks  of,  142. 

—  softening,  153. 

—  spear-head  found  in,  146. 

—  statues  by  Phidias,  140. 
— •  transparent,  141,  144. 

—  turning  hollow  pieces,  150  ;  rough 

blocks,  149;  rings,  151. 

—  veneers,  154;  veneer  saws,  807. 

—  walrus,  tusks  of,  139. 

—  weight  of  tusks  of,  142. 

—  wheels  for  polishing  of,  1122. 


J. 


JACARANDA-WOOD.     See  ROSE-WOOD,  103. 

Jacinth,  or  Hyacinth.     See  ZIRCON,  1126. 

Jack  plane,  478. 

Jade,  1069. 

Jak-wood  (Artocarpus  integrifolia),  88. 

James,  Mr.   J.,    mode   of    opening   horn, 

123. 
Japanning,  plain   and    ornamental   works, 

1404  ;   preparation  of  wood   for,  1405  ; 

polishing  japanned  works,  1069. 
Jaques,  Mr.,  on  woods,  65. 
Jargoon.     See  ZIRCON,  1126. 
Jasper,  172,  1069. 
Jeffery,  Mr.  J.,  patent  respirators,  method 

of  punching  plates  for,  944. 
Jeffrey,  Dr.,  chain-saw  for  surgery,  801. 
Jet,  162,  1069. 
Jewelled  drawplates  for  wires,  174. 

holes  for  watch  pivots,  173,  178. 
Jewellers'  rouge,  see  OXIDE  OF  IRON,  1083. 

—  work-bench,  731. 

Jewellery,  doublets  or  stones  in  two  thick- 
nesses,  1340. 

—  enamelled  works  of,  1059. 

—  facetting  gold  and  siver  works  of, 

1184  ;  steel,  1182. 

—  foils  for  setting  gems,  &c.,  1339. 

—  polishing.     See  ENAMELS,  1059  ; 
GOLD,   1063  ;   SAWDUST,  1093  ;  SILVER- 
SMITHS' WORK,  1097. 

Johnson,   Mr.  W.,   on    working   Foggintor 

granite  quarry,  170. 
Joinery  woods,  shrinkage  of,  50. 
Joints,  joinery,  clamped,  55  ;  dovetail,  55  ; 
glued,  58  ;  mortise  and  tenon,  56. 

—  knuckle  or  hinge,  formed  with  files 

and  cutters,  894. 

—  rule  and  compass,  893. 

—  sheet-metal,  angle,  391 ;  surface,  393. 

—  snuff-box,  &c.,  895. 
Joint-saw  for  drawing  instruments,  729. 
Joint-wire  made  by  drawing,  429. 
Jones,  Mr.  W.,  cutters  for  screw  dies,  603. 
Jones,  Messrs.,  patent  for  forging  wrought- 

iron  tubes  for  gun-barrels,  965. 


Jordan,  Mr.  T.  B.,  patent  carving-machh 
for  wood,  soft  stones,  &c.,  954  j  on  harden- 
ing steel  magnets,  245. 

Juniper- wood  (Juniperus) ,  88. 


K. 


KEIR,  MR.  PETER,  employment  of  chilled 
cast-iron  punches  for  red-hot  metal,  259  ; 
cutters  for  screw  dies,  603. 

Kelly,  Mr.  M.,  quannet  for  horn  and  tortoise- 
shell,  839  ;  applied  to  scraping  zinc  plates, 
for  anastatic  printing,  1023. 

Key-groove  cutter,  with  many  points,  by 
Messrs.  Whitworth  &  Co., 
990. 

engine  for  cutting  key-ways  in 
wheels,  900. 

Keyhole  saw,  712. 

Kiabooca-wood,  38,  88. 

King-wood,  89. 

Kittoe,  Mr.  G.  D.,  expanding  half-round  bit, 
1009 ;  vases  made  of  egg-shells  by, 
155. 

Knowles,  Mr.  J.,  on  dry  rot,  22. 

Kourie-wood  (Dammara  australis).  See 
PINES,  100. 


LABURNUM-WOOD  (Cytisus  Laburnum),  89. 
Lace-wood   (Platanus).      See   PLANE-TREE, 

101. 

Lac  employed  for  making  corundum  and 
emery  wheels,  1070. 

—  properties  of,  as  a  basis   for  varnish, 

1375. 

—  varnishes,  preparation  of,  1392;  bleach- 
ing, 1393. 

Lacker  for  brass,  1395  ;  for  wood,  1392. 
Lackering  hardwood  turned  works,  1413. 

—  management  of  the  brush  in,1409. 

—  metal    works,    1406  ;    bronzed, 

1413  ;  circular,  1409  ;  flat, 
1408  ;  methods  of  heating, 
1407. 

Ladles  for  iron-founding,  369. 
Lancashire  and  Sheffield  files,  819. 

—        wire  gages,  with  their  values  in 
decimal  parts  of  an  inch,  1013. 
Lance-wood  (Cruatteria  virgata),  89. 
Lapidary  work,    general    remarks,    1302 ; 
routine  of  the   process   of  working 
stones  of  different  degress  of  hard- 
ness, illustrated  generally  under  the 
heads  ALABASTER,  1034  ;  CARNELIAN, 
1044  ;  SAPPHIRE,  1091  :— 
Agate,  1033. 
Alabaster,  slitting,  roughing,  smoothing 

and  polishing,  1034. 
Amateurs'  apparatus  for,  341. 
Amber,  161,  1036. 


INDEX. — VOLS.    I.    TO    III. 


1444 


Lapidary  work : — 

Aquamarine,  1037. 

Avanturine,  artificial  and  natural,  1037. 

Bench,  amateurs',  1342;  ordinary,  1305. 

Beryl,  1037. 

Bloodstone,  1037. 

Brilliant  cut,  1321,  1328,  1335. 

Cadrans,  or  Geneva  tool,  for  facetting, 
1337. 

Cannel  coal,  1043. 

Carbuncle,  1041. 

Carnelian,  slitting,  roughing,  smoothing, 
and  polishing,  1044. 

Cat's-eye,  1046. 

Cement  stick  for  supporting  thin  stones, 
1313. 

Chalcedony,  1046. 

Charging,  slicer  with  diamond  powder, 
1310;  flatting  mill,  1314. 

Chrysoberyl,  1048. 

Chrysolite,  1048. 

Chrysoprase,  1048. 

Cloth-mill  for  polishing  shells,  rounded 
stones,  &c.,  1121. 

Convex  stones,  1045,  1316. 

Coral,  1048. 

Crane  for  slicing,  amateurs',  1342  ;  or- 
dinary, 1311. 

Cullasse  or  cullet,  1323,  1328. 

Cutting  beads,  &c.,  1317. 

—  bevilled     edges    or    chamfers, 

1315. 

—  coral  works,  1320. 

—  cylindrical  and  conical  forms, 

1316. 

—  edgesof  stones,  to  definite  forms, 

1315. 

—  facets.     See  FACETTING. 

—  flat  surfaces,  1045, 1307,  1314. 

—  flutes  in  seal  handles,  1319. 

—  heart-shaped  stone,  1317. 

—  holes,  large  and  small,  1320. 

—  hollowed  surfaces,  1318. 

—  mouldings,  1318. 

—  oval  holes,  1320. 

—  rounded  surfaces,  1045,  1316. 

—  seal  handles,  1318. 

—  shields  for   signet   rings,  &c., 

1317. 

—  tallow-tops,  1316. 
Diamond,  cutting,  17  6, 1322, 133 1,1 334. 

powder,  preparation  of,  1052  ; 
mortars  for  crushing  and  grinding, 
1309. 

Doublets,  1340. 

Drilling  large  and  small  holes,  1320. 
Elvans,  1054. 
Emeralds,  1054;  form  of  facetting,  1321, 

1327. 

Facetting,  general  remarks  on,  1045. 
—        adaptation   of    the  form   of 
the  cutting  to  that  of  the 
stone,  1321. 


Lapidary  work  : — 

Facetting,  amateurs'  apparatus  for  cut- 
ting facets,  1343  ;  table  of 
divisions  for,  1345. 

—  brilliant  cut,  general  remarks 

on,  1328. 

—  Cadrans,  or  Geneva  tool,  for 

cutting  facets,  1337. 

—  crystals,  1385. 

—  cullasse,    or     cullet.     1323, 

1328. 

—  dental  cut,  1336. 
diamonds,  176,  1322,  1331, 

1334. 

—  different     forms     of,    1321, 

1335. 

—  double  brilliant  cut,  1333. 

—  double  skill  facets,  1332. 

—  emeralds,  1321,  1327. 

—  foundation  squares,  1330. 

—  full  brilliant  cut,  1331. 

—  gim  or  germ  peg,  1306, 1324, 

1328. 

—  girdle  of  the  stone  in,  1323, 

1328. 

—  guides  for,  amateurs'  appara- 

tus,  1343;    Geneva    tool, 
1337. 

—  half  brilliant  cut,  1329. 

—  Lisbon  cut,  1333. 

—  opake  stones,  1321,  1334. 

—  pastes,  1322,  1335. 

—  preparation    of    stones   for, 

1323. 

—  rose  cut,  1322,  1334. 

—  skill   facets,   1330  ;    double, 

1332. 
split  brilliant  cut,  1332. 

—  square  cut,  1321. 

—  star  cut,  1336. 

—  table  of  the  stone,  1321, 1328. 

—  thickness  of  stones  in,  1321, 

1326. 

—  thin  stones,  1325,  1334. 

—  trap  brilliant  cut,  1332. 

—  trap  cut,  1321;  one  height, 

1 323 ;  for  small  stones,  1 335 ; 
two  and  three  heights,  1336. 

—  under  facets,  1332. 

—  under  squares,  1329. 

—  water  basil,  1324. 

—  x   cut,  1336. 
Felspar,  1060. 
Fictitious  gems,  1338. 

Flat  surfaces,  slicing,  1 307 ;  smoothing 

and  polishing,  1045,  1314. 
Flint,  1061. 
Fluorspar,  1061. 
Garnet,  1062. 

Gim  or  germ  peg,  1306,  1328. 
Girdle  of  stone,  1323, 1328. 
Glass,  1062. 
Granite,  1063. 
E  E  2 


1445 


INDEX. VOLS. 


TO    III. 


Lapidary  work : — 

Hacking   or  jarring    metal   mills  for 

polishing,  1044. 
Half  brilliant  cut,  1329. 
Jade,  1060. 
Jasper,  1069. 
Jet,  1069. 
Lapis  lazuli,  1070. 
Lavas,  1070. 
Lisbon  cut,  1332. 
Metallic  foils,  1339. 

Mills.    See  WHEELS,  1 1 1 3,  1 1 1 7,  1 121, 
1303. 

—  balls,  for  hollow  works,  1318. 

—  cloth,  for  rounded  works,  1121. 

—  flatting,  1045,  1313. 

—  leather,  1118. 

—  moulding,  1318. 

—  roughing,  1312. 

—  slitting,  1307;  velocity  of,  1034, 

1311. 

—  wood,  1035,  1117. 

Mortars    for    crushing   and    grinding 
diamond  powder,  1309. 

Nippers  for  rounding  stones,  1051,1315. 

Opal,  1082. 

Painting  transparent  stones  to  imitate 
gems,  1339. 

Pastes,  1339. 

Pebbles,  1085. 

Polishing,  1035,  1044,  1092. 

Porphyry,  1086. 

Quartz,  1087. 

Rose  cut,  1322,  1334. 

Sapphire,  slitting,  smoothing,  and  polish- 
ing, 178,  1091. 

Seasoning  the  slicer,  1310. 

Serpentine,  1093. 

Slicer  or  slitting-mill,  1098,  1307, 1310. 

Square  cut,  1323,  1326,  1335. 

Star  cut,  1336. 

Table,  of  facetted  stones,  1323. 

Trap  cut,  1321,  1323,  1326,  1335. 

Turquoise,  1101. 

Water  basil,  1315,  1324. 

X  cut,  1336. 

Zircon,  1126. 
Lapping  cutlery,  1115. 

—  facets  on   gold   and   silver,  1184  ; 

steel  jewellery,  1182. 

—  flat  works  in  metal,  1075, 1181. 

—  screw  heads,  Geneva  tool  for  small 
screws,  1185. 

Laps,  or  metal  wheels,  for  grinding  and  po- 
lishing, 1113. 

—  action  and  durability  of,  1116. 

—  annular,  for  large  works,  1181. 

—  Barclay's  artificial  emery  stone  for, 

1057. 

—  brass,  used  by  opticians,  1116. 

—  casting,  1115. 

• —    construction  of,  1114. 
»—    copper,  uses  of,  1117. 


Laps,  cutlers',  1114. 

—  dressing,  1038,  1115. 

—  durability  and  action  of,  1116. 

—  Geneva  tool,  for   lapping    heads   of 

small  screws,  1185. 

—  hacking,  to  retain  grinding  powders, 

1044,  1065. 

—  iron,  uses  of,  1 1 1 6. 

—  lapidaries',  1045,  1113,  1117,  1312. 

—  lead,  uses  of,  1117. 

—  marble-workers',  1113, 1210. 

—  metals  employed   for,  and  their   re- 

spective purposes,  1116. 

—  pewter,  tin,  and  zinc,  uses  of,  1117. 
Larch-wood,  growth  of,  20.     See  also  PINES, 

100. 

Lariviere's  method  of  punching  perforated 
sheet-metals,  943. 

Lassell,  Mr.  W.,  machine  for  polishing  spe- 
cula, 1289. 

Lathe,  general  employment  of  the,  in  the 
arts,  3. 

—  backstay,  for    cutting  long   slender 

works,  634. 

—  Besson's  screw  cutting,  616. 

—  change  wheels,  employed  for  cutting 

screws,  624  ;  computing  trains  of, 
626. 

—  circular  saws  fixed  on  chucks  in,  752 ; 

on  spindles,  754. 

—  drills  and  boring  bits,  545,  564, 100  . 

—  founders',  for  turning  cores,  &c.,  362. 

—  French  screw  mandrel,  613. 

—  Grandjean's  screw-cutting,  616. 

—  grinding  and  polishing,  amateurs',  for 

ordinary  works,  1131  ;  Mr.  C. 
Varley's,  for  lenses  and  specula, 
1269. 

—  guide  screws  and  change  wheels  for 

screw  cutting,  621. 

—  mandrels,  grinding  conical  bearings 

of,  1253,  1255  ;  cylindrical,  1237, 
1246,  1250. 

—  polishing,  1074. 

—  screw  cutting,  by  hand  in  common, 

611. 

—  screw   or   traversing  mandrels    for, 

612. 

—  slide  rests,  fixed,  with  change  wheels 

for  screw- cutting,  621;  brackets  for 
wheels,  623  ;  compared  with  tra- 
versing rests,  625  ;  driven  by 
bands,  627. 

—  slide  rests,  traversing,  with  change 

wheels  for  screw-cutting,  624  ; 
back-stay,  634  ;  clasp  nut,  632; 
rotation  of  tools  and  reversing  the 
motion,  Roberts's  and  Shanks's 
apparatus  for,  633. 

—  traversing    tools    for    screw- cutting, 

615  ;  Besson's  apparatus,  616 ; 
Grand  jean's,  617  ;  Hea  ley's,  619; 
Varley's,  620. 


INDEX.  — VOLS.   I.    TO    IH. 


1446 


Lead,  general  characters,  uses,  and   alloys 
of,  277. 

-  alloys  with  antimony,  293  ;  with  cop- 

per, 271,  294. 

-  casting  sheet,  pipes,  and  shot,  277. 
—     cohesive  force  of,  288  ;  alloys  of,  289. 

-  laps  for  polishing,  1070,  1113,  1117. 

-  soldering,   autogenous    process,  454  ; 
ordinary,  445. 

ither,  for  polishing,  1042.  1070  :  wheels, 
1118. 

Left-side  tool  for  turning  hard  wood,  518. 
Lemon-tree  wood.  See  ORANGE-TREE,  97. 
Lenses,  Brazilian  pebbles  for,  1050. 

cement  for  attaching  grinding  tools 

to,  1265. 

cloth  polishing-tool  for,  1268. 
curvature  of,  Ross's  sphereometer 
for  measuring,  1271. 

—  diamond,  175. 

fixing,  in  optical  instruments,  397. 

Greene,  Dr.  R.,  machine  for  grinding 
and  polishing,  1292. 

grinding,  by  hand,  1265  ;  by  ma- 
chinery, 1269  ;  object  glasses, 
1270  ;  microscope,  1273  ;  tools 
for,  1262. 

polishing,  ordinary,  on  cloth  polisher, 
1268  ;  best  on  silk,  1270  ;  mi- 
croscope, 1273  ;  tools  for,  1267. 

Ross's  sphereometer,  1271. 

—  runner  for  grinding,  1263. 
shell  for  grinding,  1263. 

—  silk  polishing-tool  for,  1270. 

templets  for  curvature  of,  1262. 

Varley's  lathe  for  grinding  and  po- 
lishing, 1269. 

Leopard- wood.     See  PALM-TREES,  97. 

Letter- wood.     See  SNAKE- WOOD,  106. 

Level,  Indian,  555. 

Lievre,  M.  le,  fusee  engine  with  inclined 
plane,  638. 

Lignum  rhodium.     See  ROSE- WOOD,  104. 

Lignum  vitse  (Guaicum),  90  ;  peculiar  struc- 
ture of,  33. 

Lime  for  polishing  bone,  &c.,  1071;  carbo- 
nate and  phosphate  of,  in  bone ;  lime 
water  used  to  darken  the  colour  of  wood, 
44. 

Limestones,  168;  polishing,  1071. 

Lime-tree  wood,  (Tilia),  90. 

Linden-tree.     See  LIME-TREE,  90. 

Lindley,  Dr.,  on  the  growth  of  wood,  17, 19. 

Linseed  oil,  qualities  of,  as  a  vehicle  for 
varnish  ;  boiling  and  clarifying,  1377. 

Lithographic  stones,  preparation  of,  1071. 

Live  oak  (Quercus  vircns),  96. 

Lloyd,  Col.  G.  A.,  on  bending  timber,  32 ; 
Bermuda  cedar,  79  ;  black  Botany-Bay 
wood,  75  ;  ebony,  84  ;  manchineel,  93  ; 
mangrove,  93  ;  kiabooca,  89  ;  teak,  47, 
108. 

Lloyd's  Registry  of  Ship-building  woods,  69. 


Loam,  grinding  and  polishing  with,  1070  ; 
moulds  for  founding,  359. 

Locust-tree  wood  (Robinia pseudacacia) ,  91. 

Loddiges,  Mr.  G.,  burrs  of  wood,  38  ;  cam- 
wood, 78  ;  collection  of  woods,  69  ;  speci- 
mens of  mangrove,  93  ;  teak,  22. 

Logwood  (Jlcematoxyloncampechianum),  91. 

Loggerhead  tortoiseshell,  127. 

Loosening  bar  for  founders,  333. 

Lund,  Mr.  W.,  method  of  mounting  and 
using  files  for  edges  of  thin  plates,  835  ; 
constructing  wooden  wheels  for  polishing, 
1115  ;  on  obviating  the  unhealthiness  of 
dry  grinding,  1112. 

Luning,  Mr.  H.,  method  of  bleaching  lac 
varnish,  1393. 


M. 


M'CuLLOCH,  MR.,  on  ivory,  141. 

Mac  Do  wall,  Mr.,  Archimedian  drillstocks, 
1003. 

Mac  Duff,  Mr.,  buhl  saw  machine,  747. 

M'William,  Mr.,  on  dry  rot,  22. 

Machell,  Mr.  T.,  circular  saw  for  deeply- 
seated  bones,  802. 

Macintosh,  Mr.,  process  for  cementation  of 
steel,  263. 

Macneil,  John,  Esq.,  on  woods,  65. 

Machines,  bending,  390. 

—  boring,  569 — 572. 

—  broaching,  575. 

block,  mortising  and  scoring,  505. 

—  buhl  sawing,  747. 

—  carving,  140,  954,  1025. 

—  comb-cutting,  794,  931. 
dividing,  631,  641,  651. 

—  drilling,  567. 

—  file  cutting,  840 — 843,1023. 

—  flattening,  399. 

—  forging,  461  ;  hammers  for,  186, 

198,  958,962. 

—  fusee  cutting,  617,  637. 

—  grinding,  for  cylindrical  surfaces, 

1242, 1244  ;  flat  surfaces,  1 156, 
1187,  1211,  1214,  1219,  1224  ; 
spheres,  lt)78,  1257  ;  spherical 
surfaces,  1244,  1269,  1280, 
1289,  1292,  1293,  1295. 

—  planing,   for   metal,  896  ;  wood, 

503,   981. 

—  paring,  900. 

—  pile  driving,  815,  961. 

—  punching,  931 — 952. 

—  sawing,  circular,  751 — 8 1 6  ;  recti- 

linear, 739—751. 

—  screw  cutting,  616 — 628. 

—  shaping  901. 

—  shearing,  916— 925. 

—  splitting,  32,  805,  982. 

—  stamping,  409,  933. 

—  tube  drawing,  430, 


1447 


INDEX. VOLS.    I.    TO    III. 


Mahogany  (Swietenia  Mahogoni),  91. 

Malachite,  1076. 

Malleability  of  metals,  376. 

Mallet,  Mr.,  Patent  for  zincing  iron,  301 ; 

palladiumizing,  302. 
method  of  describing,  regular 

and  irregular  screws  on  blank  cylinders, 

1010. 

Maltese  stone,  168. 
Mammoth  ivory,  138. 
Manchineel  wood  (Hippomane  Mancinella), 

93. 

Mangrove  wood  (Rliizophora  Mangle) ,  93. 
Mannheim  gold,  composition  of,  268. 
Manton,  Mr.  J.,  Patent  for  amalgamating 

lead  shot,  278. 
Maple-wood  (Acer),  93;  cause  of  bird's-eye 

figure,  38. 

Maracaybo  wood,  94. 
Marble,  general  treatment  of,  166. 

—  block  for  polishing,  1089,  1199. 

—  cleaning  polished  works  in,  1200. 

—  engraving  and  etching,  167. 

—  inlaying,  167,  1201. 

—  liner  for  supporting  small  pieces, 

1198  ;  inlaid  works,  1201. 

—  machinery  for  working,  1202. 

—  —    flat  surfaces  ;  revolving  lap  or 

sanding  plate  for  small 
works,  1210;  grinding  bed 
for  large  slabs,  Mr.  J.  Tul- 
loch's  patent,  1211. 

—  —    mouldings ;  grinding  bed  for 

rectilinear,  1214;  circular, 
1215;  polishing,  1217. 

—  —     sawing  ;  large  blocks,   1202  ; 

large  slabs,  Mr.  J.  Tulloch's 
patent,  1203  ;  feed  apparatus  for 
sand  and  water,  1205  ;  ripping 
bed  for  narrow  slips,  1206  ;  cir- 
cular works,  1208. 

—  mouldings  worked  by  hand,  1199  ; 

machine,  1214. 

—  polishing  ;  carved,  sculptured,  and 

turned  works,  1076;  flat  surfaces, 
1198  ;  mouldings,  1200  ;  machine 
for,  1215  ;  rubbers  for,  1089, 
1199. 

—  rubbing  and  smoothing  large  slabs, 

1197  ;  small,  1198. 

—  fillets  and  mouldings,  1200. 

—  runners  for  smoothing  slabs,  1196. 

—  sawing,  Frame  saw,  1190  ;  feed  or 

supply  of  sand  and  water,  1 1 92  ; 
grub  saw  for  small  pieces,  1195  ; 
management  of  the  saw,  1194  ; 
setting  out  blocks  for  cutting  into 
slabs,  1193. 

—  turning,  167. 

Marbles  for  children,  method  of  grinding, 

1078. 
Marking  gage  for  wood,  487  ;  application 

of,  501. 


Marquetry,  general  practice  of  sawing,  737; 
plain  woods  best  for,  43  ;  printing  the  pat- 
terns, 7  38  ;  saws  for,  732  ;  smoothing  and 
polishing  marquetry  in  various  materials, 
1079. 

Marshall,  Mr.,  "  New  wood,"  113. 

Masonry.     See  MARBLE. 

Mastic,  qualities  of  as  a  basis  for  varnish, 
1376  ;  varnish,  1396. 

Materials  from  the  Animal  kingdom,  117; 
Mineral  kingdom,  158  ;  Vegetable  king- 
dom, 13. 

Matrice  for  type-founding,  324. 

Maudslay's  Messrs.,  boring  bit  with  loose 
cutters,  1008;  punching  engine  for  boilers 
and  tanks,  950. 

Maudslay,  Mr.  Henry,  methods  of  origin- 
ating screws  with  inclined  knife,  581, 641 ; 
lever  adjustment  for  total  length,  644  ; 
improvements  in  screwing  tools,  646. 

May,  Mr.,  on  chilled  iron  castings,  259. 

Mayers,  Mr.  A.,  patent  machine  for  cutting 
splints  for  Chemical  matches,  982. 

Measures,  gages  at  present  used  for 
measuring  the  thickness  of  sheet  metal 
and  wires,  and  proposals  for  a  new  system 
of  gages  founded  on  the  decimal  sub- 
divisions of  the  standard  inch,  1011. 

Medlar  tree  wood  (Mespilus  germanica),  94. 

Meerschaum,  161,  1080. 

Mercury,  general  characters  and  uses  of, 
278  ;  amalgam  used  by  dentists  for  stop- 
ping teeth,  970. 

Metals,  general  properties  of,  181. 

—  catalogue  of  metals  and  alloys  com- 

monly employed  in  the  mechanical 
and  useful  arts,  265. 

—  tabular  view  of  some  of  the  pro- 

perties of  metals,  viz.,  Brittleness, 
Chemical  Equivalents,  Ductility, 
Fusibility,  Hardness,  Linear  dila- 
tions by  heat,  Malleability,  Power 
of  conducting  heat,  Tenacity, 
290  ;  cohesive  force  of  metals, 
287  ;  alloys,  289. 

—  albata,  279  ;  polishing,  1036. 

—  antimony,  265;  expansion  in  cooling, 

293.     ' 

—  Babbet's    anti-friction    metal     for 

bearings,  &c.,  970. 

—  Bath  metal,  268. 

—  bell  metal,  270. 

—  Biddery  ware,  286. 

—  bismuth,  265  ;  expansion  in  cooling, 

293. 

—  British  plate,  279  ;  polishing,  1036. 

—  brass,  composition  of  various  kinds, 

268,  273  ;  various  methods  of 
making,  311  ;  bronzing,  1411  ; 
dipping,  1410  ;  lackering,  1406  ; 
polishing,  1038. 

—  Britannia  metal,  285,  31 1 ;  polishing, 

1041. 


INDEX. VOLS.    I.    TO    III. 


1448 


Metals,  bronze,  antique  and  modern,  269, 
272. 

—  bronzing,  1411. 

—  cohesive  force  of,  287,  297. 

—  Copper  and  its  alloys,  266,  294  ; 

cohesion  of,  297  ;  white  copper. 
279. 

—  ductility  of,  295,  423. 

—  elasticity  of,  377. 

—  electrum,  279;  polishing,  1036,1054. 
fusible  metals  and  alloys,  266,  435. 

—  German  silver,  279;  polishing,  1036. 

—  gilding  metal,  268. 

—  gold  and  its  alloys,  273 ;  Jeweller's 

coloured  golds,  276  ;   polishing, 
1063. 

—  iron,    manufacture    of    cast,    182 ; 

wrought,   186  ;   polishing,   1046, 
1072,  1126. 

—  lead,  277,  1070. 

—  malleability  of,  376. 

—  Mannheim  gold,  268. 

—  mercury,  278, 

—  Mosaic  gold,  268, 

—  Muntz  metal,  268. 

—  nickel,  278. 

—  palladium,  279. 

—  pewter,   271,  284,  310;   polishing, 

1085. 

—  pinchbeck,  268. 

—  platinum,  280,  302. 

—  pot-metal,  271,  273. 

—  rhodium,  281. 

—  rigidity  of,  378. 

—  shot  metal,  277. 

—  similor,  268. 

—  silver,  282  ;  polishing,  1097. 

—  speculum  metal,  270. 

—  steel,  manufacture  of,  191. 

—  tin,  283;  polishing,  1099. 

—  type  metal,  277. 

—  zinc,  285 ;  malleable,  295  ;  polishing, 

1126. 
Micrometer  screws,  Mr.  Allan's  method  of 

cutting,  647. 
Microscopic  examination  of,  scales,   651  ; 

screws,  645  ;  woods,  14,  28. 
Miers,  Mr.,  lightness  of  corti9a  wood,  29  ; 

collection  of  woods,  69. 
Mills,  glass-cutters,  1298  ;   lapidary's  flat- 
ting, 1113,  1302,  1313  ;  moulding,  1318  ; 

slitting,  1307  ;  Saw-mills,  circular,  783  ; 

rectilinear,  741  ;  veneer,  809. 
Milne,  Mr.,  cutting  teeth  of  small  circular 

saws,  753. 
Miniature  leaves,  cutting  with  circular  saws, 

808. 
Mineralogical   solids,  models  in  wood  cut 

with  circular  saw,  769. 
Minerals,  general  remarks,  table  of  hard- 
ness, 158  ;  treatment  dependent 
on  structure,  159  ;  chucking  in 
the  lathe,  160. 


Minerals,  agate,  general  characters  of,  1 72 ; 
polishing,  1033  ;  staining,  1339. 

—  alabaster,     general     methods     of 

working,  164 ;  lapidary's  me- 
thod, 1034  ;  polishing,  1032  ; 
cleaning,  164,  1035,  1200. 

—  alumina,  base  of  corundum,  emery, 

ruby,  &c.  1030,  1036. 

—  amber,   turning,    161  ;   polishing, 

1036. 

—  amethyst,  1036. 

—  aquamarine,  1037. 

—  asteria,  see  SAPPHIRE,  1091. 

—  avanturine,    real    and    artificial, 

1037. 

—  beryl,  1037. 

—  bloodstone,  1037. 

—  carbon,  extreme  hardness  of,  1029, 

1034  ;  see  also  CHARCOAL,  1047  ; 
and  DIAMOND,  1052. 

—  carbuncle,  1044. 

—  cannel   coal,  general  methods  of 

working,  162  ;  polishing,  1043. 

—  carnelian,    172  ;    lapidary's   me- 

thods of  cutting,  smoothing,  and 
polishing,  1044. 

—  cat's-eye,  1046. 

—  cements  for  chucking  in  the  lathe, 

160. 

—  chalcedony,  1046. 

—  chalk,  preparation  of,  and  use  for 

polishing,  1046. 

—  chrysoberyl,  1048. 

—  chrysolite,  1048. 

—  chrysoprase,  1048. 

—  Charnley-forest  stone.    See  HONE- 

SLATES,  1065. 

—  clay,  ordinary  modes  of  working, 

160  ;  Prosser's  patent  process 
for  works  made  of  dry  clay  with 
dies,  957  ;  props  used  for  sol- 
dering, 977  ;  clay  for  polishing, 
see  LOAM,  1071. 

—  coral,  cutting  and  polishing,  1049, 

1320. 

—  crystal,  lenses,  &c.  1050. 

—  corundum,   wheels,   rubbers,   &c. 

for  grinding  and  polishing, 
1049. 

—  diamond,  general   treatment  and 

uses  of,  175  ;  action  of  glazier's 
diamond,  176;  diamond  powder, 
preparation  of,  for  lapidaries', 
watch-jewellers',  and  seal-en- 
gravers' use,  1052  ;  diamond 
tools,  for  drilling,  etching,  grind- 
ing, turning,  &c.  178  ;  fictitious 
diamonds,  1053. 

—  elvans,  general  modes  of  working, 

169,1054.  See  also  PORPHYRY, 
1086. 

—  emerald,  1059. 


1449 


INDEX. VOLS.    I.    TO    III. 


Minerals,  emery,  preparation  of,  in  various 
forms,  for  grinding  and  polish- 
ing, 1054. 

—  felspar,  1060, 

—  flint,  general  uses  and  treatment 

of,  1061  ;  splitting  gun-flints, 
160. 

—  fluor-spar,  turning  vases,  &c.  168  ; 

polishing,  1061. 

—  freestones,  sawing,  1189  ;  turning, 

169;  smoothing,  1062,  1169. 

—  gannister-stone,  for  polishing  cut- 

lery, 1062. 

—  garnet,  1062. 

—  granite,  quarrying   and   prepara- 

tory treatment,  169  ;  grinding, 
smoothing,  and  polishing,  1063. 

—  gritstones,      or     grindstones,    of 

various  kinds,  viz.  Newcastle, 
Bilston,  Sheffield,  and  Wickers- 
ley  grindstones  ;  Sheffield  blue- 
stone,  carpenter's  rubstone,  De- 
vonshire batts,  Yorkshire  and 
Congletou  grits,  1064. 

—  hone- slates  of  various  kinds,  viz. — 

Norway  ragstone,  Charnley- 
forest,  Devonshire,  Idwall  and 
Welsh  oilstones  ;  cutlers'  green, 
German  razor,  and  Peruvian 
hones;  Ayr,  Scotch,  snake,  blue, 
and  grey  polishing  stones,  1065. 

—  hyacinth.     See  ZIRCON,  1126. 

—  iron-stone,  for  polishing  edges   of 

cutlery,  1067, 1155. 

—  jade,  1069. 

—  jasper,  172,  1069. 

—  jargoon.  See  ZIRCON,  1126. 

—  jet,  162,  1069. 

—  lapis  lazuli,  1070. 

—  limestones,  166,  1071. 

—  malachite,  1076. 

—  marble,  general  treatment  of,  166  ; 

general  modes  of  working  by 
hand  and  machinery,  1190; 
polishing,  1076. 

—  meerschaum,  161, 1080. 

—  mica,  159. 

—  opal,  1082. 

—  oriental    stones.     See    SAPPHIRE, 

1091. 

—  plasma,  1085. 

—  porphyry,  169, 1086. 

—  potstone,  166  ;  polishing,  1087. 

—  pumice-stone,  1087. 

—  quartz.     See  CRYSTAL,  1050. 

—  ruby,   173,    178.      See   also   SAP- 

PHIRE, 1091. 

—  sand,  1090. 

—  sandstones,  169.     See  also  GRIND- 

STONES, 1064. 

sapphire,  173  ;  varieties  of,  and 
lapidaries'  methods  of  working, 
1091. 


Minerals,  sard,  and  sardonyx,  1092,1366. 

—  satin-stone,  164,  1092. 

—  serpentine,  166,  1093. 

—  slate,  general  modes  of   working, 

165,  1097. 

—  steatite,  166,  1098. 

—  topaz,  173,  1099. 

—  touchstone,  1100. 

—  tripoli,  1100. 

—  Turkey  oilstone,  1081. 
turquoise,  1101. 

—  zircon,  1126. 
Miser  for  boring  earth,  522. 
Mitre-block  for  planing  angles,  503  ;  plane, 

481. 

Mora- wood  (Mora  excelsa),  94. 
Morney,   Mr.,   on    Cuticaem    branco,  and 

vermo,  41. 
Mortars  for  crushing  and  grinding  diamond 

powder,  1309. 
Mortise,  chisel,  716  ;  gage,  488. 

—  joints,  56,  716  ;  cut  with  circular 

saw,  993. 
Mortising  ships'  blocks,  Brunei's  engine  for, 

505. 
Mosaic  gold,  composition  of,  268. 

—      works,  glass,  ancient  Egyptian,  767. 

—  marble,  general  method  of  work- 

ing, 1201. 

—  wood,  763  ;  Berlin,  or  square, 

767  ;  combining  the  patterns, 
765  ;  glueing  up,  765  ;  po- 
lishing, 1079  ;  sawing,  764. 

Mosatahiba-wood.     See  MUSTAIBA,  74. 

Moslings,  for  removing  grease  from  metal 
works,  1080. 

Moulds,  foundry.     See  FOUNDING. 

—  slate,  engraved  in  intaglio  for  cast- 

ing, 166. 
Moulding,  horn- works,  125. 

—  planes,    action   and    imperfections 

of,  489  ;  cutters  of  curvili- 
near section  suggested  to  avoid 
"dragging,"  491. 

—  tools,  for  turning  hard  woods,  519  ; 

sharpening,  1176,  1441;  drills 
and  cutters,  1170. 

—  tortoiseshell   works,   129  ;    boxes, 

131. 

—  wood,  45. 

Mouldings,  marble  and  stone,  working  by 
hand,  1199  ;  machine  for  recti- 
linear mouldings,  1214  ;  circu- 
lar, 125. 

wood,  glueing,  59  ;    sticking,  or 
working  with  the  plane,  492. 

Muffle,  for  enamelling,  1059. 

Muir's  planing  machine  for  wood,  505. 

Mulberry-tree  wood  (Morus),  94. 

Muntz  metal,  for  sheathing,  &c.,  268. 

Murraya  wood.     See  Box  WOOD. 

Muschenbroek  on  cohesive  force  of  metals 
and  alloys,  287,  297. 


INDEX. VOLS.    I.    TO    III. 


1450 


Museums,  collections  of  woods,  68 ;  economic 
geology,  172. 

Mushet,  Mr.,  on  manufacture  of  iron  and 
steel,  183,  185,  193,286. 

Music,  printed  from  wires,  427. 

Musket  barrels,  forging  by  hand  and  ma- 
chinery, 223,  965  ;  broaching,  575. 

Mustaiba  wood,  94. 


N. 


NACREOUS  SHELLS,  preparation  of,  and  work- 
ing, 119  ;  polishing,  1093. 

Nail-head  tools,  for  turning  iron,  526. 

Nails,  forging,  231  ;  Clifford's  patent  for 
rolling  and  punching,  949  ;  made  by 
punching  and  shearing  machines,  947  ; 
fibres  of  palm-trees  used  as  nails,  18. 

Naphtha,  qualities  of  as  a  vehicle  for  varnish, 
1380. 

Narwal  tusks,  or  ivory,  1 39. 

Nasmyth,  Mr.  James,  crane-ladle,  for  pour- 
ing iron,  370  ;  cupola  of  large  size,  367  ; 
description  of  Mr.  W.  Lassell's  machine 
for  polishing  specula,  1289  ;  direct  action 
steam-hammer,  958  ;  experiments  on  the 
tenacity  of  wrought-iron,  and  the  in- 
fluence of  treatment,  460  ;  grinding  ma- 
chine for  flat  surfaces  on  large  metal 
works,  1187  ;  portable  hand-drill,  568  ; 
steam  pile-driving  engine,  961  ;  tool 
gage,  534. 

Neale,  Mr.  J.  Wilson,  on  the  preparation 
of  varnishes,  1380. 

Needles,  straightening  soft  wire  for,  424. 

Nettle-tree  wood  (Celtis  Australis),  95. 

Newbury,  Mr.,  flexible  and  endless  saw,  for 
cutting  curvilinear  and  straight  works, 
751. 

Newcastle  grindstones,  1064. 

Newton's  fusible  alloy,  266. 

"  New  wood,"  Mr.  Marshall's,  113. 

Nicaragua  wood,  95. 

Nicholl's,  Mr.  S.,  stop  or  clamp,  for  planing 
benches,  980 

Nickel,  general  characters,  uses,  and  alloys 
of,  278  ;  alloy  used  in  tinning,  451. 

Nippers,  cutting  for  wires,  &c.,  905. 

—  lapidary's  and  optician's,<for  round- 
ing lenses  and  stones,  1051, 
1265,  1315. 

Norway  ragstone,  1065. 

Nose-bits,  for  boring  wood,  540. 

Nowell,  of  loam  foundry  moulds,  359. 

Nut,    Areca    or    betel,     111;      polishing, 
1037. 

-  cocoa-nut  shell,  111. 

-  coquilla,  111  ;  polishing,  1049. 

—    corosos,    or    ivory,    112  ;     polishing, 

1049. 
Nutmeg- wood.     See  PALMS,  97. 


0. 


OAK-WOOD,  (Quercus),  95  ;  silver  grain  of, 

40  ;  colour  of  bog  oak,  44. 
Octahedron,  cut  with  the  circular  saw,  775  ; 
cubo-octahedron,    781  ;     ex-octahedron, 
782. 

Oil,  linseed,  qualities  of,  as  a  vehicle  for 
varnishing  ;  boiling,  and  clarifying, 
1377. 

—  of  turpentine,  qualities  of,  as  a  vehicle 

for  varnish,  1378. 

—  varnishes,  general  instructions  for  pre- 

paration of,  1380. 

Oilstones,  Charuley-forest,  Devonshire  and 
Welsh,  &c.,  1065  ;  Turkey  oil- 
stones, slips,  and  powder,  1081. 
—      sharpening  cutting  tools  on,  1141. 

Oldham,  Mr.,  method  of  annealing  and 
hardening  steel  cylinders,  dies,  and  plates 
for  transfer  engraving,  243,  255  ;  chain 
for  working  spur  wheels,  940. 

Oliver,  or  small  lift  hammer  worked  by  the 
foot,  for  forging,  962. 

Olive-wood  (Olea  europea),  96. 

Omauder-wood.     See  COROMANDEL,  82. 

Onyx,  application  of  the  term  by  gem  en- 
gravers, 1366. 

On  win,  Mr.  R.,  banding  plane,  488. 

Opal,  1082. 

Optical  glasses.     See  LENSES. 

Orange-tree  wood  (Citrus  Aurantium},  97. 

Organ  pipes,  pewter,  277  ;  zinc,  285. 

Ornamental,  characters  of  woods,  34. 

—          drills  and  cutters,  sharpening, 
1171. 

Osborne,  Mr.  H.,  patent  for  forging  wrought- 
iron  tubes  for  gun  barrels,  966. 

Ox,  bone,  120  ;  horn,  121. 

Oxide  of  iron  for  polishing,  analysis  of,  1029; 
ordinary  mode  of  manufacture,  Mr.  A. 
Ross's  mode  of  preparing  oxide  of  iron 
for  polishing  lenses,  &c.,  1082  ;  Lord 
Rosse's  mode  of  preparing,  for  polishing 
specula,  1083  ;  jewellers'  rouge,  specula 
iron  ore,  1083  ;  tripoli,  1084. 

Oxides  of  tin,  analysis  of,  1029;  ordinary 
mode  of  manufacture,  Mr.  A.  Ross's 
method  of  preparing  for  polishing  lenses, 
&c.  See  PUTTY  POWDER,  1088. 

Oxmantown,  Lord.     See  ROSSE,  EARL. 


P. 


PADDLE  SHAFTS,  forging  large,  196. 

Palisander- wood,  99. 

Palladium,  general  character  and  uses  of, 

279  ;   polishing,    1085  ;    Mallett's   palla- 

diumizing  process,  302. 
Palmer,  Mr.  H.,  bisecting  gage  for  marking 

center  lines,  488. 


1451 


INDEX. VOLS.    I.    TO    III. 


Palm  trees,  viz. — areca,  or  betle  nut,  cocoa 
nut,  niepere,  palmyra,  and  prickly  pole, 
97  ;  growth  and  section   of  palms,  17  ; 
fibres  used  as  nails,  1 8. 
Panels  and  frames,  57  ;  panel-saws,  708. 
Paper  making,  rollers  for  finishing,  method 
of   grinding    perfectly   true   with 
water  only,  1237. 

—  varnish,  1398. 

Parallel  guides   for   circular    saw-benches, 

small,  758  ;  large,  790. 
Paring  knife,  for  preparing  turnery  woods, 
25,_474, 

—  machines,  for  cutting  mortises  and 

cuvilinear  works  in  metal,  900. 

Parquetage,  732  ;  polishing,  1079. 

Parting  tools  for  hard  wood,  518  ;  ivory 
rings,  151  ;  soft  wood,  517. 

Partridge-wood  (Heisteria  coccinea),  99. 

Pastes,  cutting  and  polishing,  1085.  See 
also  LAPIDARY  WORK. 

Patterns  for  foundry  moulds,  327.  See  also 
FOUNDING. 

Paxton's  planing  machine  for  wooden  sash 
bars,  981. 

Payne's  patent  process  for  preserving  timber 
from  decay,  953. 

Peach-wood.     See  NICARAGUA-WOOD,  95. 

Pear-tree  wood  (Pyrus  communis)  99. 

Pearl-shell,  iridescence,  mode  of  working, 
119;  relative  qualities  of  different  kinds, 
120  ;  polishing,  1094. 

Pebbles,  Brazilian,  for  lenses,  1050 ;  polish- 
ing, 1085. 

Pellatt,  Mr.,  on  annealing  glass,  238. 

Peon- wood.     See  POON-WOOD,  102. 

Pendulums  made  of  wood,  47. 

Pencils,  saws  for  cutting  cedar,  757. 

Pens,  Hawkins1  "everlasting  pen,"  281  ; 
machine  for  cutting  quill-pens,  931  ;  steel 
pens,  hardening,  249  ;  punching,  942. 

Perkins',  Mr.,  method  of  annealing  and 
hardening  steel  plates  for  tranfer  en- 
graving, 254  ;  preventing  distortions  in 
hardening,  256;  screw-joints  for  cast- 
iron  pipes,  680  ;  tubes  and  fusible  plugs 
for  warming  apparatus  and  steam  boilers, 
226. 

Pernambuca-wood,  (Ccesalpina  echinata). 
See  BRAZIL-WOOD,  77. 

Peruvian,  hone,  1066  ;  wood,  100. 

Pewter,  composition  of,  and  mixing,  271, 
284,  310  ;  polishing,  1085 ;  soldering,  449. 

Phosphate  of  lime,  in  bones,  ivory,  shells,  &c. 
118. 

Picker  out,  for  foundry  moulding. 

Pickling,  brass  and  iron  castings,  375,  851, 
1410. 

Piedmont  screw  wheels,  for  silk  mills,  668. 

Piercing  saws  for  silversmith's  works,  forms 
of  frames  and  method  of  using,  730  ;  set- 
ting out  and  sharpening  the  teeth,  692. 

Pigeon  wood,  100. 


—      Coo 


Piles,  American  pile  driving  machine,  815  ; 
circular  saws  for  cutting  off,  815  ;  Nas- 
myth's  steam  pile  driving  machine,  961. 

Pincer  tongs,  for  forging,  201. 

Pinchbeck,  composition  of,  268. 

Pine  and  fir  woods  (Pinus),  1 00. 

Pinion  wire,  426. 

Pitch  block,  for  chasing,  413. 
—    polisher,  for  specula,  1277. 

Pietra  dura,  167. 

Pit  saws,  702  ;  sawing  straight  and  curvi- 
linear works,  707. 

Plane-tree  wood  (Platarms),  101. 

Planes,  general  remarks  on,  472  ;  counter- 
parts of  form  to  be  wrought,  474. 

—  astragal,  489. 

—  banding,  488. 

—  bench,  general  purposes  and  struc- 

tures of,  476. 

—  capping,  493. 

—  Chinese,  478. 

—  compass,  475. 

—  construction  of  mouth,  wedge,  &c., 

477. 

—  Continental  jack  plane,  478. 

>per'sjointer,478;  crose,  and  sun- 
lane,  488. 

drawer  bottom,  486 

fences  or  slips  for,  485. 

Fillister,  side,  485  ;  Silcock  and 
Lowe's  patent  iron,  978. 

grooving,  484. 

handrail,  475. 

hollows  and  rounds,  492. 

irons  for,  action  of  single  and  double, 
479  ;  adjusting,  489  ;  modification 
of  double  irons,  498  ;  moulding, 
498 ;  oblique,  485 ;  grinding  and 
sharpening,  bench,  496,  1136, 
1144;  moulding,  1138. 

jack,  478. 

metal,  482 ;  Silcock  and  Lowe's 
patent,  978. 

mitre,  481. 

moulding,  action  and  imperfections 
of,  489  ;  cutters  of  curvilinear 
section  to  avoid  f<  dragging,"  491; 
Spring  of  moulding  planes,  493. 

pitch,  or  inclination  of  plane  irons, 
common,  York,  middle,  and  half 
pitches,  482. 

plough,  486 ;  Falconer's  circular, 
979  ;  Silcock  and  Lowe's  patent, 
978. 

rebate,  478  ;  side,  489  ;  skew,  485  ; 
square,  490. 

reglet,  487. 

rounder,  488. 

router,   487  ;     Mr.    Lund's 
router,  979. 

scaleboard,  504,  981. 

scoring  points  for,  485. 

scraping,  483. 


INDEX. VOLS.    I.    TO    III. 


1452 


Planes,  slit  deal,  486. 

—  Smith's,  for  metal,  483;  application 

in  producing  flat  surfaces,  867. 

—  smoothing,  478. 

—  spokeshave,  475,  479. 

—  stops  for  fillisters  and  other  planes, 

485. 

—  sun-plane  for  coopers,  488. 

—  surfacing,   general   proportions  of, 

476. 

toothing,  483. 

Planing  metal,  hand  or  smith's  plane,  483  ; 
application  in  producing  flat 
surfaces,  867. 

—  machines  for,  comparative  sketch 

of  the  application  of  the  plan- 
ing machine  and  of  the  file, 
896  ;  planing  bevelled  edges, 
898  ;  prismatic  and  pyramidal 
works,  899 ;  rectangular  blocks, 
897. 

—  tools  for,  general  remarks  on  the 

principles  of  their  formation, 
531  ;  papers  on  the  principles, 
of  tools  for  turning  and  planing 
metals,  by  C.  Babbage,  Esq., 
F.R.S.,  984  ;  by  the  Rev.  Prof. 
Willis,  A.M.,  F.R.S.,  991. 
Babbage's  cutter  bar  or  tool 

holder,  988  ;  tool  with  many 

points,  990. 
Clement's    finishing   tools   for 

brass  and  iron,  537. 
different  forms  contrasted,  532. 
effects  of  flexure  in,  533. 
finishing    or    springing    tools, 

grinding,  983,  1141. 
HoltzapffePs  with   cutter  bar 

triangular  blades,  535. 
Nasmy th's  tool  gage,  534. 
side  cutting,  536,  983.  , 
Planing  slate,  165. 
Planing  wood,  modes  and  order  of  using  the 
planes,  498. 

—  benches,    holdfasts,    stops,    &c., 

494. 

—  cross,  or  irregular  grained  woods, 

484. 

—  edges  of  boards,  502. 

—  flat  surfaces,  499. 

—  machines  for,  by  Bentham,  Bra- 

mah,  Brunei,  Burnett  and 
Poyer,  Muir,  and  Paxton,  503 
—506. 

—  machines,    comparison    between 

hand  and  machine  planing,  507 ; 
fixed  and  revolving  cutters, 
981. 

—  machines,  Esdaile  and  Margrave's 

for  scaleboard,  981  ;  Mayer's 
for  splints  for  chemical  matches, 
982;  Paxton's  for  sash  bars, 
981. 


Planing,  machines,   sharpening    cutters  for 
mouldings,  1176. 

—  mitre-block  for  angles,  503. 

—  mouldings,  493. 

—  squaring  up,  500. 

—  shooting  boards  for,  application  of, 

—  straight  edges,  499  ;  mutual  com- 

parison of  three,  873. 

—  winding  sticks  for,  application  of, 

500. 

Planometer,  application  in  filing  flat  sur- 
faces, 866;  general  forms  and  instructions 
for  originating,  875. 

Plasma,  1085, 

Plaster  of  Paris,  Mr.  Franchi's  mode  of 
imitating  ivory  carvings,  1085  ;  moulds 
for  casting,  324,  343. 

Platinum,  general  characters,  uses,  and 
method  of  preparation,  280 ;  fuses  readily 
with  tin,  &c.,  302. 

Pliers,  bell-hangers,  906. 

—  cutting,  905. 

—  forging,  234. 

—  pin  tongs,  862. 

—  punch,  930. 

—  saw  set,  697. 

—  shanks,  for  rounding  glass  disks  and 

lenses,  1265. 

—  sliding  tongs,  862. 

—  tongs  for  forging,  201. 

Pliny,  on  woods  used  by  the  Romans,  64. 
Ploughs  for  grooving  wood,  486  ;  Falconer's 
circular,  979  ;  Silcock  and  Lowe's  patent, 
978. 
Plumier's   method   of   originating   screws, 

579. 

Plumbago,  conversion  of  cast-iron  into,  368. 
Plumbers,  solder,  285  ;  soldering  iron,  445. 
Plum-tree  wood  (Prunus),  102. 
Point  tool,   for  turning   hard  wood,   518; 

grindstones,  1108;  marble,  167. 
Polishing,  descriptive  catalogue  of  the  appa- 
ratus, materials,  and  processes  for  grind- 
ing and  polishing,  commonly   employed 
in  the  mechanical  and  useful  arts,  1038. 
Polishing  Apparatus  : — 

Block  for  marble  slabs,  1089,  1199. 
Bobs  for  spoons,  &c.,  1038,  1119. 
Bouldering  stone  for  smoothing  metal 

laps,  1038. 

.Brushes,  1041  ;  wheel  brushes,  1122. 
Buff  leathers  and  sticks,  1042;  wheels, 

1118. 
Burnishers,  general  action,  applications 

and  forms  of,  1042. 
Caps,  or  metal  laps  with  wooden  centers, 

1044,  1114. 

Cloth  polisher  for  lenses,  1267  ;  wheels 
for  lapidaries,  ivory  workers,  &c., 
1121. 

Cutler's  long  wheel,  1105. 
Emery  wheels,  1120. 


1453 


INDEX. VOLS.    I.    TO    III. 


Polishing  Apparatus : — 

Geneva  tool,  for  heads  of  small  screws, 
&c.,  1185. 

Glass-cutter's  wheel,  1297. 

Glazer's.  or  glazing  wheels,  1063, 1118. 

Lapidary's  bench,  ordinary,  1 304 ;  ama- 
teur's, 1341. 

Laps,  or  metallic  wheels,  1113. 

Lathes,  ordinary,  1074;  amateur's,  1 34 1 ; 
Varley's,  for  lenses  and  specula, 
1269. 

Machines  for  flat  surfaces,  metal,  1121 ; 
marble,  1215  ;  plate-glass,  1221  ; 
sheet-glass,  1225. 

Machines  for  spherical  surfaces  of  lenses 
and  specula,  Dr.  Greene's,  1292  ; 
Rev.  W.  Hodson's,  1293  ;  Mr.  Las- 
sell's,  1289  ;  Earl  Rosse's,  1280. 

Polishers,  cloth,  1 048 ;  for  lenses, 
1267. 

Polishers,  or  leather  wheels  with  wooden 
centres,  1119 

Polishers,  pitch,  for  specula,  for  plane 
surfaces,  1231  ;  for  spherical  surfaces, 
1278  ;  preparation  of  the  pitch,  1277; 
Earl  Rosse's,  1284  ;  Mr.  Lassell's, 
1 292. 

Polishers,  silk,  for  lenses,  1720. 

Polishers,  wax,  for  lenses  for  micro- 
scopes, 1273. 

Rubbers,  1089  ;  for  French  polishing, 
1090,  1414  ;  marble  works,  1089, 
1199,  1216,  1217  ;  plate-glass,  1222; 
sheet-glass,  1226. 

Rumble,  or  shaking  machine  for  small 
works,  1090. 

Tools  for  lenses,  1267,  1270. 

Wheels,  general  application  and  me- 
chanical arrangements  of,  1102  ; 
brush,  1122  ;  cloth,  1121  ;  com- 
position, or  factitious  stone,  1112  ; 
leather,  1118  ;  metal,  1113,  wood, 
1117. 
Polishing  materials  : — 

Analysis  of  the  principal  polishing  and 
grinding  materials,  viz. — diamond, 
sapphire,  ruby,  corundum,  emery, 
rottenstone,  flint,  tripoli,  polishing 
slate,  Bohemian  stone,  Turkey  hone, 
pun  dee-stone,  oxide  of  iron,  oxide, 
of  tin,  and  chalk,  1029. 

Alumina,  1030,  1036. 

Ayr,  Scotch,  or  snake- stone,  1065. 

Blue  polishing-stone,  1066. 

Bohemian-stone,  167. 

Carbon,  1030,  1044. 

Charcoal,  1047. 

Chalk,  ordinary,  and  prepared  by 
double  decomposition,  1046. 

Cloth,  1048  ;  for  lenses,  1267. 

Colcothar  of  vitriol.  See  OXIDE  OF 
IRON,  1082. 

Congleton  grit,  1064. 


Polishing  materials  : — 

Corundum,  1049. 

Crocus,  various  modes  of  manufacture. 
See  OXIDE  OF  IRON,  1082. 

Devonshire  batts,  1064. 

Emery,  preparation  of  powder,  cake, 
cloth,  paper,  and  sticks,  1054  ;  Bar- 
clay's artificial  emery-stone,  1057  ; 
white  emery,  1060. 

Felt.     See  CLOTH,  1048,  1267. 

Fish  skin,  1060. 

Flanders-brick,  1C61. 

Flint,  1061. 

Gannister-stone,  1062. 

Glass-paper,  1062. 

Grey-stone,  1066. 

Grit-stones,  1064. 

Iron-stone,  1067. 

Leather,  1042,  1070,  1118. 

Lime,  1071. 

Loam,  1071. 

Oil-stone  powder,  1081. 

Oxide  of  iron,  various  modes  of  manu- 
facture, 1082. 

Oxide  of  tin,  modes  of  manufacture, 
1088. 

Pumice-stone,  1087. 

Putty-powder,  modes  of  manufacture, 
1088. 

Red  stuff.     See  OXIDE  OF  IRON,  1082. 

Rottenstone,  1089,  1101. 

Rouge.     See  OXIDE  OF  IRON,  1083. 

Sand,  1090  ;  paper,  1091. 

Saw-dust,  109:1 

Silex,  1030,  1097. 

Snake-stone,  1065. 

Specular  iron  ore,  methods  of  pre- 
paration, 1083. 

Trent-sand,  1091. 

Tripoli,  1084,1100. 

Whiting,  1101. 
Polishing  processes  : — 

—  preliminary    observations,   1028; 

cleanliness    highly    important, 
1032. 

—  agate,  1034. 

—  alabaster,  1035. 

—  albata  spoons,  &c.,  1036. 

—  amber,  1036. 

—  amethyst,  1036. 

—  avanturine,  1037. 

—  betle  nuts,  1037. 
bloodstone,  1037. 

brass,  cast  works,  1041  ;  door- 
plates,  1039  :  flat  works,  1039; 
with  charcoal,  1047  ;  stamped 
works,  1040;  turned  works, 
1038  ;  bronzing,  1411;  dipping, 
1410;  lackering,  1406. 

—  braziers'  works,  1040,  1049. 

—  britannia  metal,  1041. 

—  bronze,    1041  ;    bronzing    brass, 

1411. 


INDEX. VOLS.    I.    TO    III. 


1454 


Polishing  processes  : — 

—  buhl  works.       See    MARQUETRY 

WORK,  1079. 

—  burmese  bowls,  &c.,  1417. 

—  cannel  coal,  1043. 

—  carbuncle,  1044. 
• —         carnelian,  1044. 

—  cast-iron,     common     works,    as 

stoves    and  fire  irons,    1046  ; 
machinery,  1074. 

—  cat's-eye,  1046. 

—  chalcedony,  1046. 

—  chrysoberyl,  1048. 

—  chrysolite,  1048. 

—  chrysoprase,  1048. 

—  copper  -  plates,     with      charcoal, 

1047 ;  coppersmiths'  works, 
1049,  1049. 

—  coquilla  nut,  112,  1049. 

—  coral,  1049. 

—  corosos,  or  ivory  nut,  1049. 

—  crystal,  1050  ;  lenses  of,  1267. 

—  curling,    flat    surfaces   in   brass, 

1039. 

—  cut-glass,  1300. 

—  cutlery,  1051. 
diamond,  176. 

edge  tools.     See  CUTLERY,  1051. 

—  electrum,  1054. 

—  emerald,  1059. 

—  enamels,  1059. 

—  facets,  1045,    1183,   1184,  1321, 

1343. 

—  felspar,  1060. 

—  fluor  spar,  1061. 

French  polishing,  1392,  1415. 

—  gem  engravers'  works,  1362. 

—  glass,   1062  ;   cut,    1300  ;    drops, 

1301;  plate,  1222  ;  sheet,  1'225. 

—  gold,  1063,  1084  ;  faceted  works, 

1185. 

—  granite,  172,  1063. 

—  hardwood,  turned  works,  1413. 

—  harp  plates,  1039. 

—  horn,  1065. 

—  inlaid  works,  1079. 

—  iron,  cast,  common  works,  1046  ; 

machinery,  1074  ;  wrought, 
common  works,  1126  j  ma- 
chinery, 1072. 

ivory,   carved,  filed,  and  turned 
works,  1067. 

—  jade,  1069. 

—  japanned  works,  1069. 

—  jasper,  1069. 

—  jet,  1043,  1069. 

—  jewellery.     See  GOLD,  ENAMELS 

SAWDUST,  and  SILVER. 

—  lapidary  work.    See   ALABASTER 

1035;  CARNELIAN,  1044  ;  and 
SAPPHIRE,  1091. 

—  lapis  lazuli,  1070. 

—  lapping,  cutlery,   and  edge-tools 


'olishing  processes  : — 

1115;  facets,  1045,1183,1184, 
1321, 1343  ;  flat  works  in  hard- 
ened  steel,  &c.,  1075,  1180. 

—  lead,  1070. 

—  lenses,     ordinary,    1267  ;    best, 

1270  ;  microscope,  1273. 

—  limestones,  1071. 

—  lithographic  stones,  1071. 

—  malachite,  1076. 

—  marble,  flat  works  by  hand,  1 1 9  8 ; 

machinery,  1215;  mouldings 
by  hand,  1200  ;  machinery, 
1217  J  ornaments,  sculptured 
and  turned  works,  1076. 

—  marquetry  works,  in  metal,  wood, 

&c.,  1079. 

—  mathematical  instruments,  1039. 

—  meerschaum,  1080. 

—  mosaic  works,  1079. 

—  nacreous  shells,  1093. 

—  opal,  1082. 

—  painted  works,  1084. 

—  Palladium,  1085. 

—  parquetage,  1079. 

—  pastes,  1085. 

—  pebbles,  1085. 

—  pewter,  1085. 

—  platinum,  1086. 

—  porcellaneous  shells,  1093. 

—  porphyry,  171,  1086. 

—  pot-stone,  1087. 

—  quartz,  1050,  1088. 

—  razors,  1051,  1120. 

—  reflectors  for  light-houses,  1097. 

—  reisner  works,  1097. 

—  rhodium,  1089. 

—  ruby,  1090. 

—  sard,  1092. 

—  sapphire,  1091. 

—  satin-stone,  1092. 

—  scaglioia,  1093. 

—  screw  threads,  1073. 

—  sculpture,  1077. 

—  seal  engravers'  works,  1 362. 

—  serpentine,  1093. 

—  shells,  1093. 

—  silversmith's  works,  1097. 

—  slate,  1097. 

—  soapstone,  1098. 

—  specula,  by   hand,  1231,    1279  ; 

machinery,  Earl  Rosse's,  1280, 
1287;  Mr.  W.  Lassell's,  1286  ; 
Dr.  R.  Greene's,  1292  ;  Rev. 
W.  Hodgson's,  1293. 

—  spheres,  in  hardened  steel,  &c., 

1261. 

—  statuary,  1077. 

—  steatite,  1 098. 

—  steel,  cutlery,  1051;  facets,  1183; 

flat  works,  1075,  1180;  plates 
for  engraving,  1047;  spheres, 
1261 ;  turned  works,  1072. 


1455 


INDEX. VOLS.    I.    TO    III. 


Polishing  processes  : — 

—  telescope  tubes,  1039. 

—  tin,  1099. 

—  topaz,  1099. 

—  tortoiseshell,  1099. 

—  turquoise,  1101. 
_        turtleshell,  1101. 

—  varnished  works,  1084,  1101. 

—  watchwork,    brass,    1040 ;    steel, 

1075;  screws,  1185. 

—  whalebone,  1102. 

—  woods,    flat  works,  1125  ;    mar- 

?uetry,  mosaic,  parquetage,  &c., 
079;    turned    works,    1123; 
French  polishing,  1415. 

—  wrought -iron,     common    works, 

1226;  machinery,  1072. 

—  zinc  plates,  1126. 

—  zircon,  1126. 

Polyhedra,  cutting  with  the  circular  saw,774. 
Poon  wood  (Calophyllum),  102. 
Poplar  wood  (Populus),  102. 
Porcellaneous  shells,  117;  polishing,  1093. 
Porphyry,  general  modes  of  working,  169  ; 

turning,  171  ;  polishing,  1086. 
Pot-metal,  composition  of,  271,  273. 
Pot-stone,  166  ;  polishing,  1087. 
Pow  and  Lyne,  Messrs.,  machine  for  cutting 

the  teeth  of  combs,  794. 
Presses,  coining,  936  ;  fly  for  punching,  934 ; 

knee  or  toggle  joint,  937  ;  moulding  for 

tortoiseshell,  131. 

Price's  patent  drying  room  for  wood,  27. 
Princes  wood,  102. 

Printing  calico  and  muslin  with  wires,  427. 
Prize  wood,  102. 

Profile  tools,  for  turning  hardwood,  519. 
Prosser,  Mr.  R.,  patent  process  for  works 

made  of  dry  clay,  957  ;  patent  for  forging 

wrought-iron  tubes,  967  ;  synoptical  table 

of  the  manufacture  of  wrought-iron  tubes, 

964. 
Pruning  saws,  712  ;  sharpening,  694, 

—  scissors  and  shears,  911. 
Prussiate    of    potash,    employed   for  case- 
hardening,  262. 

Pumice  stone,  1087. 

Pump-boring  bits,  540. 

Punches,  general  characters  of,  926  ;  used 
without  guides,  927 ;  with 
simple  guides,  930  ;  in  fly 
presses,  934. 

—  annular,  for  leather  washers,  928. 

—  bolsters,  and  guides  for,  932. 

—  chilled  cast-iron,  for  red  hot  metal, 

259. 

—  circular,  for  soft  materials,  927  ; 

for  sheet  metal,  928. 

—  coin,  compensation  for  errors  in, 

938. 

—  comb  teeth,  931. 

—  cutting,    927,    930 ;    sharpening, 

1177. 


Punches,  envelope  cutters,  928. 

—  figured,  928  ;  in  detached  pieces, 

combined  for  ornamental  de- 
signs, 946. 

—  forging,  215. 

—  gun  wadding,  927. 

—  harp  makers',  for  long  mortises, 

930. 

—  Jeffery's,  for  patent  respirators, 

944. 

—  Lariviere's,  for  perforated  sheet 

metals,  943. 

—  lozenge,  927. 

—  pliers,  930. 

—  rasps,  for  cutting  the  teeth  of,  830. 

—  rectangular,  for  long  mortises  in 

sheet  metal,  930. 

—  sharpening  cutting  punches,  1177. 

—  sheet  metal,  387,  928,  930,  943, 

944. 

—  Smith's,  for  red  hot  metal,  929. 

—  wafer,  927. 
Punching,  buhl  works,  947. 

—  buttons,  938. 

—  chains  with  flat  links,  large  for 

machinery,  939  ;  small  for 
jewellery  and  watches,  940. 

—  combs,  931. 

—  cut  brads,  947. 

—  disks  for  coin,  938. 

—  experiments  on  the  force  required 

to  punch  holes  in  wrought-iron 
and  copper,  by  Messrs.  Coult- 
hurst  and  Hick,  951. 

—  Jeffery's  patent  respirator,  944. 
Punching  machines  : — 

Coining  presses,  936. 

Drop  hammer,  933. 

Engineers,  950. 

Fly  presses,  general  construction,  934  ; 
worked  by  steam  power,  936  ;  fol- 
lower, 935  ;  puller  off,  936  ;  stops 
for  position  of  works,  939. 

Force,  933. 

Hammer  press,  932. 

Knee-joint  presses,  937. 

Lever  presses,  933,  950. 

Maudslay's,  for  boilers  and  tanks,  950. 

Pen-making  machines,  931. 

Portable,  for  boiler  plates,  leather  straps, 
&c.,  933. 

Roberts'  punching  and  shearing  ma- 
chine, with  lever  for  boiler  plates, 
920  ;  portable  with  slides,  921. 

Stops  for  position  of  works,  939  ;  to 
regulate  penetration  of  punches,  937. 

Toggle-joint  presses,  937. 
Punching,  nails  and  brads,  947. 

—  percussion  caps,  942. 

—  perforated  sheet  metal,  943. 

—  steel  beads,  1183  ;  pens,  942. 

—  teeth  of  combs,  931  ;  saws,  942. 

—  washers,  939. 


INDEX. VOLS.    I.    TO    III. 


1456 


Punching  watch  chains,  941. 

Purple  heart-wood,  102  ;  purple  wood,  103. 

Putty  powder,  modes  of  manufacture   for 

ordinary  and  optical  purposes,  1087. 
Pyramidal  works  in  wood,  cutting  with  the 

circular  saw,  770. 
in  sheet  metals,  made  by 
joining,  382;    raising, 
408. 

Pyrolignite  of  iron,    used   for   preserving 
timber,  114. 


Q. 


QUANNET,  for  working  horn    and  tortoise- 
shell,  838. 

—       Kelly's,  839  ;  applied  to  scraping 
zinc  plates,  for  Anastatic  print- 
ing, 1023. 
Quarrying  granite,  practice  at  the  Fogginter 

quarry,  170. 
Quarter-hollow,  and  quarter-round,  tools  for 

turning  hardwoods,  519. 
Quartz,  1088.     See  also  CRYSTAL,  1050. 
Quassia  wood   (Quassia   amara,  Simaruba 

amara,  and  Picrcena  excelsa),  1 03. 
Queen  wood,  103. 

Quince-tree  wood  (Cydonia  vulgar  is),  103. 
Quincy,  Monsieur  de,  on  ancient  statues  of 

ivory,  140. 
Quill  bits,  for  boring  wood,  539. 


R. 

RACK  SAW,  724. 

Ragging,  or  straggling  grindstones,  1109. 

Rag-stone,  1065. 

Railway  bars,  rolling  out,  1 88. 

—  wheels,     forging,    227  ;    Gooch's 

method  of  manufacturing  and 
hardening  steel  tires  of,  257. 
Raising  sheet- metal  works,  with  the  hammer, 
398  ;  by  spinning   in  the   lathe, 
395  ;  by  stamping,  409  ;  by  alter- 
nate spinning  and  stamping,  974. 
ball  and  cross  of  St.  Paul's  cathe- 
dral, 405. 

—  chasing,  413. 

—  Foxall's  patent  method,  by  alternate 

spinning  and  stamping,  974. 

—  French  horn,  407. 

hammers  covered  with  cloth,  411; 

effects  of  solid  and  hollow  blows 

compared,  399. 
hemispheres,  402. 
jelly  moulds,  408. 

—  malleability   of    the     sheet-metals, 

398. 
planishing  plated  works,  411. 

—  proportioning  size  of  metals  to  the 

object,  398. 


Raising,  reversing,  412. 

—  Szentepeterie's  specimen,  in    alto- 

relievo,  414. 

—  thimbles,  by  stamping,  410. 

—  tools,  peculiarities  in,  4JO;  anvils 

and  hammers  covered  with  cloth, 
411  ;  pitch  block  for  chasing, 
413  ;  snarling  iron  for  deep  ves- 
sels, 412. 

—  vases   and  other  complex  works. 

406. 

Ramsden,  Mr.,  dividing  engine,  for  circles, 
method  of  ratching  the  wheel,  639  ; 
dividing  engine  for  straight  lines,  641  ; 
original  employment  of  diamond  for  turn- 
ing steel,  646  ;  screw-cutting  engine,  640. 

Rand,  Mr.,  patent  collapsible  tin  tubes, 
drawing,  431  ;  raising  by  fly  press,  681, 
977. 

Randolph,  Elliot,  &  Co.'s  circular  saw-ma- 
chine for  hexagonal  blocks,  798. 

Ransome,  Messrs.,  patent  compressed  tree- 
nails, 29  ;  ploughshares  of  chilled  cast- 
iron,  258. 

Raoul's  files,  cut  by  machinery,  840. 

Rasps,  cutting  the  teeth  of,  830 ;  iron- 
founder's,  835. 

Razors,  grinding,  1051,  1148. 

—  hardening,  252. 

—  handles,  horn,  moulding,  125  ;  po- 

lishing, 1067  ;  ivory,  sawing  out, 
148  ;  working  and  polishing,  10 69; 
inlaying  escutcheons 'in,  134. 

—  hones   and  whetstones  of  various 

kinds  for,  1066,  1152;  Fayrer's 
swing  hone,  1060. 

—  lapping,  1115. 

—  polishing,  1120. 

—  sections  of  various  kinds,  1147. 

—  setting,   general  view  of  the  pro- 

portions and  sections  of  razors, 
1146  ;  setting  on  hone,  1154  ; 
striking  off  wire  edge,  1153  ; 
stropping,  1155  ;  tests  for  keen- 
ness, and  faulty  condition  of  edge, 
1150. 

—  strops,    1155;    Edward's     patent 

paper  for,  1057  ;  Sir  J.  Robison's 
instrument,  1177. 
Rebate  planes,  478  ;  side,  489  ;  skew,  485  ; 

square,  490. 

Rebates  cut  with  the  circular  saw,  793. 
Rectilinear  saws.     See  SAWS,  RECTILINEAR. 
Red  gum  wood.     See  GUM  WOOD,  86. 
Red    Sanders    wood    (Pterocarpus    santa- 

linus),  103. 
Red  stuff,   for  polishing.     See    OXIDE   OF 

IRON,  1082. 
Reglet  plane,  487. 
Regnault,  Mr.  M.  V.,  analyses  of  iron  and 

steel,  236. 
Reid,  Mr.  Adam,  screw  engine  with  inclined 

plane,  639. 


H57 


INDEX. VOLS.    I.    TO    III. 


Reinward,  Professor,  on  Kiabouca  wood, 
89. 

Reisner  work,  732  ;  polishing,  1079. 

Renton,  Mr.  A.  M.,  hydraulic  machine  for 
cutting  off  copper  bolts,  924. 

Resins  and  gums  in  woods,  30. 

—  commonly  employed  in  making  var- 
nishes, viz. — amber,  anime,  colophony, 
or  common  resin,  'copal,  damar,  lac, 
mastic,  and  sandarac,  respective  qualities 

'    of,   1374—1376. 

Rewa-rewa  wood,  41 . 

Rhinoceros-horn,  122. 

Rhode,  Mr.  J.,  on  furniture  polish,  1418. 

Rhodium,  general  characters  of,  used  for 
the  nibs  of  pens,  281  ;  grinding  and  polish- 
ing, 1089. 

Rhomboid,  cutting  with  the  circular  saw, 
774  ;  rhombic  dodecahedron,  776. 

Ribbon-rollers,  made  with  semi-cylindrical 
cutters,  491. 

Richemont,  Count  de,  airo-hydrogen  blow- 
pipe, 454. 

Riddle  for  straightening  wire,  425. 

Rider's  machine  for  forging  spindles,  &c., 
461. 

Rifflers  for  sculptors,  837. 

Right-side  tool,  for  turning  hard  woods, 
518. 

Rigidity  of  metals,  378. 

Rimers,  for  taper-holes  in  72. 

Rings,  forging,  226. 

Rip-saws,  708. 

Riveting,  angle-joints  for   toilers,  &c.,  392. 

Riviere's  drill  for  metal,  547. 

Roberts,  Mr.  Richard,  alloy  balance,  298  ; 
bar-cutting  machine,  923  ;  bending  ma- 
chine for  sheet-metal,  390  ;  bolt-screwing 
machines,  608  ;  broach,  with  detached 
blades,  574  ;  case  hardening,  262 ;  pin 
drill,  551  ;  portable  punching  and  shear- 
ing machine  with  slides,  921  ;  punching 
and  shearing  machine,  with  lever  for 
boiler-plates,  920  ;  slide-lathe  for  cutting 

•     screws,  633. 

Rogers,  Mr.,  comb-cutting  machine,  130. 

Rollers,  bending   and  flattening,  for  sheet 
metal,  390. 

—  fixed,   for    drawing,   correctional 

process  for  coin,  428. 

—  glazier's  vice  for  drawing  window- 

lead,  428. 

—  grinding,    ordinary,   1236  ;    accu- 

rate, for  paper-making,  1237. 

—  ribbon,  made  with  semi-cylindrical 

cutters,  491. 

Rolling  sheet  metals,  376. 
Rolls  used  in  iron  works,  187  ;  for  taper 

works  and  railway  bars,  188  ;  steel  bars, 

193. 
Roose,   Mr.,   patent  for  forging  wrought- 

iron  tubes,  968. 
Rose's  fusible  alloy,  266. 


Rose- wood  (Mimosa),  103. 

Rose  tta- wood,  103. 

Ross,  Mr.  A.,  alloy  of  platinum  and 
silver,  281  ;  alloy  of  zinc  and  speculum 
metal,  286 ;  composition  of  speculum 
metal,  270  ;  cutting  micrometer  screws, 
648  ;  grinding  optical  glasses,  1229  ; 
making  lacker  for  brass,  1396  ;  polishing 
plane  specula,  1231  ;  preparing  oxide  of 
iron  for  polishing  optical  glasses,  &c., 
1082  ;  preparing  putty-powder,  1087  ; 
sphereometer  for  measuring  curvature  of 
lenses,  1271 ,  washing  emery  for  grinding 
optical  glasses,  1055. 

Rosse,  Earl,  casting  six-foot  speculum, 
462  ;  composition  of  speculum  metal, 
270;  on  Edwards'  elliptical  polisher  for 
specula,  1278  ;  machine  for  grinding  and 
polishing  three-foot  speculum,  1280  ;  six- 
foot  speculum,  1286  ;  mould  for  casting 
specula,  371  ;  polishing  plane  specula, 
1231  ;  preparing  peroxide  of  iron  for 
polishing  specula,  1083  ;  preparation  of 
polisher  for  specula,  1277  ;  supporting 
large  specula,  to  prevent  flexure,  1288. 

Rottenstone,  1089  ;  analysis  of,  1029;  pre- 
paration for  polishing,  1101. 

Rouge,  various  modes  of  manufacture.  See 
OXIDE  OF  IRON,  1082. 

Rounder,  488. 

Round  tools,  for  turning  hardwoods,  519. 

Router  gage,  for  wood,  488. 

—  plane,   487  ;    Mr.    Lund's     screw- 

router,  979. 

Roving  smooth  grindstones,  1109. 
Royls,  Mr.  G.,  patent  for  forging  wrouglit- 

iron  tubes,  967. 
Royle,  Dr.,  M.D.,F.R.S.,L.S.,G.S.,  &c.  &c., 

botanical  notes  on  woods,  65,  71 — 110. 
Rubbers,  for  polishing,  1089. 

—  corundum,  1049. 

French  polishing,  1090,  1414. 

—  marble  workers',  for  slabs,  1196, 

1089,  1199  ;  fillets  and  mould- 
ings, 1200. 

Ruby,  analysis  of,  1029  ;  general  modes  of 
working,  173.  See  also  SAPPHIRE, 
1091. 

—  draw-plates  for  wire,  174. 

—  holes,  for  watch  pivots,  173, 178. 

—  wood.     See  RED  SANDERS,  103. 
Rules,   contraction,   for   foundry   patterns, 

855. 

—  parallel,  for    circular    saw-benches, 

790. 

Rumble,  or  shaking  machine,  for  cleaning 
metal  castings,  346  ;  polishing  small 
metal  works,  1090. 

Runner,  for  grinding  lenses,  1263  ;  smooth- 
ing marble  slabs,  1196. 

Russian  maple  wood,  94. 

Hussell's,  Mr.,  patent  for  forging  wrought- 
iron  tubes,  225,  966,  967. 


INDEX. VOLS.    I.    TO    HI. 


1458 


Russell  and  Whitehouse's,  Messrs.,  patent 
for  forging  thin  wrought-iron  tubes  for 
boilers,  9G8. 


S. 


SALLOW-WOOD  (Salix  cuprea),  1 04. 

Sandal-wood  (  Santalum  album),  105. 

Sand,  for  foundry  moulds,  329  ;  grinding 
and  polishing,  1090;  sawing  stone,  marble, 
&c.,  1192. 

Sand-paper,  1091. 

Sand-stones,  169,  1064. 

Sanders-wood.     See  RED  SANDERS,  103. 

Sapan-wood  (Ccesalpina  Sapari),  105. 

Sapphire,  analysis  of,  1029  ;  general  treat- 
ment, 173;  lapidary's  routine  for  cutting, 
smoothing,  and  polishing,  1091  ;  varieties 
of  sapphire,  1092. 

Sard  and  sardonyx,  1992. 

Sash,  carcase,  dove-tail,  and  tenon  saws, 
713. 

Sassafras- wood  (Sassafras  qfficinalis),  105. 

Satin-wood  (Chloroxylon  Swietenia),  105. 

Satin-stone,  164  ;  polishing,  1092. 

Saunders,  Mr.  W.  Wilson,  on  woods,  65,  69. 

Saul- wood  (Shorea  robusta),  106. 

Saws,  arrangement  of  the  subject,  general 
remarks,  682. 

—  amputating,  801. 

—  annular,  crown,  or  drum,  802. 

—  back,  713;  table  of  dimensions,  699. 

—  blades,  manufacture  of,  683. 

—  bow,  or  sweep,  728. 

—  buhl,  or  inlaying,  732  ;  setting  out 

and  sharpening  the  teeth,  692. 

—  carcase,    dovetail,  sash,  and   tenon, 

713. 

—  chain,  for  surgery,  801. 

—  chair-makers,  725. 

-  circular,  common  application  to  small 
works,  752  ;  common  applica- 
tions to  large  works,  783;  speci- 
fic applications  to  large  works, 
792  ;  circular  saws  and  ma- 
chinery for  cutting  veneers,  805. 
carving,  for  ivory,  &c.,  753. 

—  correcting    distortions    with    the 

hammer,  419. 

—  cross  cutting,  701,  796. 

—  crown,    annular,   curvilinear,    or 

drum  saws,  802,  1022. 

—  dimensions,  table  of,  784. 
double,  for  mortises  and  tenons, 

&c.,  793. 

—  gas-fitters',  for  bat's- wing  burners 

753. 

—  marble  workers,  for  narrow  slips 

1206'. 
opticians',  for  springs   of,  pocke 

telescopes,  752. 
screw-head  saw,  753. 


Saws,  circular,  sectional  teeth,  for  feather- 
edged  boards,  797. 

—  segment,  for  veneers,  809. 

—  sharpening,    by   filing,    698  ;    by 

grinding,  1011. 

—  surgical,  for  deeply-seated  bones, 

802. 

—  velocity  of,  785,  809. 

—  veneer,  in  single  plates  for  small 

works,  807 ;  in  segments  for 
large  works,  809  ;  grinding,  815 ; 
table  of  dimensions,  784. 

—  compass,  lock  and  table,  711. 

—  continental  frame  saw,  726. 

—  crown,  drum,  or  annular,  802. 

—  curvilinear,  802,  1022. 

—  double,   for     cutting     combs,   723; 

racks,  247  ;  double  circular,  for 
mortises,  tenons,  &c.,  793. 

—  dovetail,  carcase,   sash,  and  tenon, 

713. 

—  dust  used  for  polishing  jewellery,  &c., 

1093. 

—  endless,  patented  by  Mr.  Newbury, 

751. 

—  felling,  700. 

—  felloe,  707. 

—  files,  for  sharpening,  689. 

—  fire- wood,  726,  740. 

—  flattening,  the  principles  and  practice 

of  flattening  thin  plates  of  metal 
with  the  hammer,  414. 

—  frame,  for  general  use,  724  ;  table 

of  dimensions,  699  ;  double  and 
single  frames  for  cutting  deals, 
&c.,  703  ;  frame-saws  for  ivory, 
146,  728  ;  metal,  729. 

—  grub,  for  small  pieces  of  marble  and 

stone,  1195. 

—  gullet-teeth,  various  forms  of,  687  : 

sharpening,  695. 

—  hammering.     See  FLATTENING. 

—  hand,    panel,    and    rip-saws,    708  ; 

angles  of  teeth,  684  ;  sharpening, 
694  ;  table  of  dimensions,  699. 

—  hardening  and  tempering,  249. 

—  Harvey's    patent    curvilinear,   reci- 

procating saws,  1022. 

—  ice  saw,  741. 

—  inlaying,  or  buhl  saws,  732  ;  setting 

out  and  sharpening  the  teeth,  692. 

—  ivory,  146,  728. 

—  joint,  for  metal,  729. 

—  keyhole,  712, 

—  lock,  compass,  and  table,  711. 

—  long,  pit,  or  whip,  702. 

—  Newbury's  endless,  or  flexible,  751. 

—  mill,  725,  743  ;  dimensions  of,  699  ; 

teeth  of,  686  ;  sharpening,  693. 

—  panel,   hand,   and   rip,    sharpening, 

694  ;  dimensions  of,  699. 

—  parallel,  with   backs,  713  ;  used   in 

frames,  724  ;  dimensions  of,  699. 

F  F 


1459 


INDEX. VOLS.    I.    TO    111. 


Saws,  peg-teeth,  sharpening,  693. 

—  piercing,  for  silversmiths,  &c.,  730  ; 

setting  out  and  sharpening  the 
teeth  of,  692. 

—  pit,   long,   and   whip,  702  ;  turning 

saw,  707 ;  dimensions  of,  699 ;  forms 
of  teeth,  687  ;  sharpening,  695  ; 
horse  for,  688. 

—  pitch   of  teeth,    explanation  of  the 

term,  683. 
•    pruning,  712  ;  sharpening,  694. 

—  rack,  724. 

—  rectilinear,  table  of  dimensions,  699. 

—  sash,  tenon ,  carcase,  and  dovetail,  713. 

—  sawpit,  for  timber,  703. 

—  screw-head,  722  ;  circular,  753. 

—  setting,  with   hammer,   696  ;    pliers 

and  saw  set,  697  ;  setting  circular 
saws,  698. 

—  sharpening,  688. 

—  buhl,  inlaying,  and  piercing  saws, 

692. 

—  circular,  698  ;  by  grinding,  1011. 

—  clamps,  for   circular,  698  ;  recti- 

linear, 688. 

—  files  used  for,  689. 

—  gullet  teeth,  695. 

—  hand-saw  teeth,  694. 

—  horse,  or  frame  for  pit-saws,  689. 

—  mill-saw  teeth,  693. 

—  peg-teeth,  693. 

—  Smith's  saw  teeth,  691. 

—  topping,  or  ranging  the  teeth  level, 

circular  saws,  698  ;  rectilinear, 
690. 

—  veneer  saws,  large  segment,  814. 

—  vices  used  for,  688. 

—  side-frame,  for  metal,  729. 

—  Smith's  frame,  729  ;  sharpening,  691. 

—  spherical,  proposed  by  Mr.  Trotter, 

803. 

—  stone,   with   teeth    for   soft   stones, 

1189;  without  teeth  for  hard 
stones,  marble,  &c.,  1190. 

—  surgical,  800. 

—  sweep,  or  turning,  728. 

—  table,  compass,  and  lock  saws,  711. 

—  table  of  dimensions  of,  circular  saws, 

784  ;  rectilinear,  699. 

—  taper,  699. 

—  teeth,  explanation  of  terms — pitch, 

points,  and  space,  683. 

—  forms     of    cross-cutting,     fleam, 

gullet,  hand-saw,  half-moon, 
Peg>  M»  an(i  skip,  teeth,  684; 
pruning-saw  teeth,  695;  Smith's 
saw  teeth,  691. 

—  punching,  942. 

—  sectional,  for  feather-edge  boards, 

797. 

« —  setting  out  and  sharpening  fine 
saw  teeth,  692  ;  revolving  screw- 
cutter  for  fine  circular  saws,  753. 


Saws,  tenon,  sash,    dovetail,  and   carcase, 

713. 
trephine  saws,  800. 

—  turning,  or  sweep,  728. 

—  veneer ;  pit,  725 ;  single  plate  circular, 

807  ;  segment,  809. 

—  whip,  long,  or  pit  saw,  702. 
Saw  machines,  circular,  751. 

—  American,  for  feather-edge  boards, 

797. 

—  beds,    supplementary    for    cutting 

bevelled  edges,  763  ;  cross-cut- 
ting large  timber,  795  ;  models 
of  crystallographical  solids,  780  ; 
prisms,  regular,  768  ;  irregular, 
773. 

—  benches  or  platforms  for  large  saws, 

788 ;  for  small  saws,  of  iron, 
756  ;  of  wood,  755. 

—  Brunei's  for  cross-cutting,  795. 

—  crown  or  curvilinear,  811,  1022. 

—  Donkin's,  for  angular  works,  799. 

—  flanges  for   small  saws,  754,  757  ; 

for  large  saws,  758. 

—  guides,  angular,  with  protractor  for 

ends    of    small    pieces,    761  ; 

for   large    circular    saw   plat- 
forms, 795. 
blocks,  for  pyramidal  pieces,  770; 

for  bevelled  edges  and  mosaic 

works,  763. 
compound,   for    complex  forms, 

799. 
cross-cutting,    for     round     and 

square  timber,  795. 

—  parallel,  for  small  saws,  758  ;  for 

large,  790;  for  irregular  pieces, 
792  ;  staves  of  casks,  804  ; 
supplementary  thicknesses  for 
thin  works,  760  ;  works  of  two 
thicknesses,  791  ;  veneers, 
808,  811. 

—  lathe    apparatus,    for   very    small 

saws,  752  ;  for  medium-sized 
saws,  754. 

—  marble,  for  narrow  slips,  1 206. 

—  platforms.   See  BEDS  and  BENCHES. 

—  power,  required  to  drive,  784. 

—  screen,  to  prevent  dust  being  thrown 

in  the  eyes,  791. 

—  spindles,  for  small  saws,  754  ;  large, 

787. 

—  stops  to  prevent  vibration  of  thin 

saws,  small,  757  ;  large,  788  ; 
hemp  packing,  789. 

—  velocities  of  saws,  784. 

— -      veneer,  small,  for  ivory,  &c.,  807  ; 
large,  for  wood,   809  ;  construc- 
tion of  the  saw,  810  ;  drag,  811. 
Saw  machines,  rectilinear,  or  reciprocating, 
739. 

—  apparatus  for  bevelled  and  curvi- 

linear works,  746,  805. 


INDEX. VOLS.    I.    TO    III. 


1460 


Saw  machines,  rectilinear,  Brunei's,  worked 
by  interior  epicycloid,  747. 

—  buhl,  cutting,  747. 

—  cross-cutting,  740. 

—  curvilinear  apparatus,  747,  805. 

—  deal-frame,  742. 

—  early,  worked  by  hand,  741  ;  foot, 

745. 

—  fire-wood,  worked  by  hand,  740. 

—  felling,  739. 

—  French,  worked  by  foot,  745. 

—  Hamilton's  patent,  for  bevelled  and 

curvilinear  works,  805. 
Hick's,  plank  frame,  744. 

—  ice-saw,     by   Lieut.   J.   W.    Hood, 

741. 

—  Lund's,  for  inlaid  and  fret  works, 

748. 

—  Mac  Duff's,  for  buhl  work,  747. 

—  marble,   for   blocks,    1202  ;   slabs, 

1203  ;  feed  of  sand  and  water, 
1203. 

—  Newbury's  endless  and  flexible  saw 

for  curvilinear  and  straight  works, 
751. 
plank-frame,  744. 

—  timber-frame,  745. 

—  Tulloch's  patent,  for  marble  slabs, 

1202. 

Willis's,  for  curvilinear  works,  749. 
Sawing,  applications  of  saws  used  by  hand  : 
back,  714  ;  frame,  727;  hand, 
709  ;  pit,  703  ;  common  appli- 
cation of  circular  saws  to  large 
works,  783 ;  to  small  works,  751 ; 
specific  applications,  783. 

—  angular    works,   horizontal,   761, 

795  ;   vertical,  763  ;  horizontal 
and  vertical,  769,  799. 

—  Berlin  mosaic  works,  767. 

—  bevelled  works,  763,  769. 

—  blocks,     for    making    mitre    and 

square  cuts,  714. 

—  blocks,  for  wood  paving,  795. 

—  brush  backs,  with  crown  saws,  803. 

—  buhl  works,  in  wood,  734  ;  in  brass 

and  pearl-shell,  736. 
chair-backs,  with  crown  saws,  803. 

—  cogs,  for  mortise  wheels,  799. 

—  combs,  teeth  of,  723,  794. 

—  counterpart,  or  inlaid  works,  731. 

—  cross-cutting,  702,  714,  761,  795. 

—  crystallographical  solids,  769  ;  pri- 

mary, 774  ;  secondary,  780. 

—  cube,  774  ;  cubo-octahedron,  781. 

—  curvilinear  works,  707,  711,  730, 

746,  800. 
deals,  with  pit-frame  saws,  703. 

—  disks,  with  crown  saws,  802. 
dodecahedron,  775.  j 
dovetails,  718. 

feather-edged     boards,    by    East- 
man's machine,  797. 


Sawing,  felloes  of   wheels,  by  hand,  707  ; 
with  crown  saws,  803. 

—  flooring  boards,  793. 

—  freestones,  1189. 

—  geometrical  and  other  solids,  769, 

774,  f79. 

—  gothic  and  other  mouldings,  798. 

—  granite,  1201. 

grooves,  rebates,  and  tenons,  761, 
793. 

—  handles  from  ivory  tusks,  147. 

—  hexagonal  blocks,  for  wood  pave- 

ment, 798. 

—  hexagonal  and  other  prisms,  768. 

—  hexahedron,  774. 

—  horse,    buhl-cutters',    732  ;    con- 

tinental, 727. 

—  icosahedron,  776. 

—  icositesserahedron,  777. 

—  iron,  721,  729  ;  red-hot,  816. 

—  irregular    pieces    of    wood    with 

circular  saws,  792. 

—  ivory    tusks     into    blocks,    146  ; 

handles  and  pianoforte  keys,  148 ; 
for  turned  works,  149  ;  veneers 
for  miniature  leaves,  154,  808. 

—  joints  of  drawing  instruments,  729. 

—  knuckle  joints,  753. 

—  marble,   by  hand,   1192  ;  by  ma- 

chinery, 1202 

—  marquetry  works,  737. 
metal,  726,  729,  816. 

—  mineralogical  solids,  769,  774,  779. 

—  mitres,  714,  762. 

—  mortises  in  ships'  blocks,  793. 

—  mosaic  works,  763. 

—  mouldings,  798. 

—  octahedron,  775  ;  cubo-octahedron, 

781  ;  ex-octahedron,  782. 

—  pierced  works,  730. 

—  piles,  under  water,  815. 

—  polygonal  prisms,  768. 

—  polyhedra,  of  various  forms,  774. 

—  porphyry,  1201. 

—  prismatic  works,  768. 

—  pyramids,  770  ;  double,  771  ;  irre- 

gular, macled,  or  twisted,  772. 

—  rebates,  grooves,  and  tenons,  761, 

793. 

—  rectangular  works,  with   circular 

saws,  759,  785. 

—  rhombic  dodecahedron,  776. 

—  rhomboid,  774. 

—  rhombuses,  for  mosaic  works,  764. 

—  round  timber,  with  circular  saws, 

759,  791  ;  with  pit-saws,  704. 

—  silversmiths'  pierced  works,  730. 

—  slate,  165,  816,  1090. 

—  spiral  veneers,  of  ivory  and  wood, 

154. 

—  staves  of  casks,  792,  804. 

—  stone,  by  hand,    1189,  1192  ;  by 

machinery,  1202. 

F  F  2 


1461 


INDEX. — -VOLS.    I.    TO    III. 


Sawing,  teeth  of,  combs,  723,  794  ;  racks, 
724. 

—  tenons,  717,  761,793. 

—  tetrahedron,  774. 

—  thick  logs,  with  two  circular  saws 

in  the  same  plane,  785. 

—  thin  boards  with  the  segment  saw- 

mill, 814. 

—  timber,  fixing  logs  on  the  saw-pit, 

703  ;  marking  out  logs  for 
planks,  705  ;  for  wainscot,  706  ; 
sawing  straight  and  curvilinear 
works,  707. 

—  trapezahedra,  777. 

—  triangles  for  mosaic  works,  764. 

—  veneers,  by  hand,  805  ;  large,  with 

segment  saws,  809  ;  small,  with 
single  plate  circular  saws,  807. 
Scagliola,  polishing  of,  1093. 
Scaleboard,  Esdaile  &  Margrave's  machine, 

for  cutting,  981  ;  plane  for,  504. 
Scales,  application  of  screws  to  the  gradua- 
tion of  scales  ;  Ramsden's  dividing 
engines,  639  ;  Donkin's,  651. 

—  contraction,  for  setting  out  foundry 

patterns,  355. 

—  contraction  of  ivory,  47,  152. 

—  Holtzapffel's  "New  System  of  scales 

of  equal  parts,"  356. 

—  protractor,  for  setting  out  polygonal 

works  in  sheet  metals,  384. 
Scissors,  principles  of  their  action  and  con- 
struction,   907;    forging,    233; 
sharpening,  909. 

—  button-hole,    flower,  grape,  lamp 

and  nail,  910. 

—  pocket,  pruning,  and  surgical,  911. 
Scoring  of  iron  castings  in  cooling,  361. 
Scotch-stone,  for  polishing,  1065. 

Scott,    Mr.   G.,  apparatus  for  boring   and 

tapping  main-pipes  for  gas  or  water,  1004. 
Scott,  Mr.,  patent  screw-joint  for  cast-iron 

and  other  pipes,  680. 
Scraper,  for  finishing  flat  surfaces,  in  metal, 

868  ;  wood,  484. 
Scraping  plane,  483. 
Scrap  iron,  manufacture  of,  197. 
Scratch  brushes,   853 ;    made    as   wheels, 

1122. 

Screws,  elementary  and  descriptive  observa- 
tions on  the  forms  and  general 
purposes  of,  577. 

—  angle  of  thread  determines  power 

of,  658  ;  importance  of  agreement 
in  screw  and  nut,  659  ;  method 
of  calculating,  657  ;  tendency  to 
burst  the  nut,  662. 

—  Allan's   method   of  cutting   micro- 

meter, 647. 

—  application  of,  to  the  graduation  of 

mathematical  scales,  639,  651. 

—  back-stay   for   cutting  long  slender 

screws  in  the  lathe,  634. 


Screws,  Barton's    method    of    originating, 
645. 

—  bench,  and  chops,  for  joiners,  495. 

—  Besson's  screw-cutting  lathe,  616. 

—  Bodmer's  chasing  tool,  629  ;  screw- 

stocks,  606  ;  tap,  585. 

—  bolt-screwing  machines,  607. 

—  box,  for  cutting  wood  screws,  593. 

—  casting,  Perkins'  &  Scott's  methods, 

680  ;  Warren's  &  Wilk's,  679. 

—  change  wheels,  for  fixed  slide-rests, 

621  ;  for  traversing  sliding-rests, 
624  ;  modes  of  computing  trains 
of,  626. 

—  chasing  tools,  used  by  hand,  611 

in  machines,  628. 

—  Chidson's   table   for  proportions   of 

small  screws  of  angular  threads, 
671. 

—  Clement's  chasing-tool,  629  ;  method 

of  originating  guide-screws,  648. 

—  compressing,  for  vices,  678  ;  Rand's 

method  for  collapsible  tubes, 
681. 

—  correcting  length  of  guide  ;  Mauds- 

lay's  method  with  lever,  644  ; 
Ramsden's  with  change  wheels, 
640. 

—  correcting  small  irregularities,  636  ; 

Barton's  method  with  two  pairs 
of  dies,  646;  Clement's  with 
chasing-tools  and  dies,  648  ;  Don- 
kin's  with  compensating  bar,  651. 

—  cutting,  by  hand,  with  dies,   593  ; 

plates,  596  ;  taps,  583. 

glass  screws,  614. 

in  lathes,    common,  611  ;    with 
traversing  mandrels,  612. 

in  lathes,  with  traversing   tools, 
615;    early     methods,     616 
fixed    slide-rest    and    change 
wheels,    621  ;    Healy's    appa- 
ratus, 619  ;  traversing  sliding- 
rest  and  change-wheels,  624 
Varley's  apparatus,  621. 

joiners',  Wright's   machine  for, 
608. 

long,  slender,  610,  634. 

—  moulds,  for  upholsterers'  fringes, 

612. 
small,  with  screw  plates,  596. 

—  wood,  593. 

Screw  dies  for  cutting  external  screws,  593 ; 
general  considerations  of  cur- 
vature and  forms  of,  599. 

—  adapted    principally   for    short 

screws,  610. 

—  Allan's  method  of  cutting  micro- 

meter screws  with,  647. 
applications  of,  601,  607. 

—  Barton's  application  of  two  pairs, 

for  correcting  minute  errors, 
646. 


INDEX. VOLS.    I.    TO    III. 


1462 


Screw  dies,  Clement's  apparatus  for,  em- 
ployed in  originating  screws, 
649. 

—  compression  of,  and  correctional 

modification  in,  602. 
employed  in  originating  screws, 
636. 

—  forms  of,  in  common  use,  602. 

—  interferences    of    curvature   in, 

599. 

—  irregularities  of  screws  cut  with, 

601. 

—  Jones's  cutters  for,  603. 

—  Keir's  cutters  for,  603. 
left-hand,  substitute  for,  604. 
Maudslay's    improvements     in, 

646. 

—  proportions    of,    600  ;    medium 

generally  preferred,  602. 

—  regulating,  for  plug  taps,  676. 

—  Robisoii's,  603. 

—  Ross's  method  of  cutting  micro- 

meter screws  with,  648. 

—  two  pairs   of,   sometimes   used, 

601,  646. 

Screw  die-stocks  for  cutting  external  screws, 
596  ;  general  remarks  on 
action  of,  608. 

—  Bodmer's  screw  stocks,  606. 

—  double  and  single  chamfered,  598. 

—  early  forms  of,  597. 

—  modern  forms  of,  598. 

—  plier,  597. 

—  Whitworth's  screw  stocks,  605, 

609. 

Screws,  double  threads,  cut  accidentally 
with  dies,  861 ;  intentionally  with 
guide  screw  and  change  wheels, 
622. 

—  durability  of  screws  and  nuts,  662. 

—  forging,  678. 

—  forming  by  peculiar  modes,  679  to 

681. 

—  Fox's  bolt  screwing  machine,  607. 

—  French  screw  mandrel  lathe,  613. 

—  fusee  engine  for  cutting,  with  change 

wheels,     617  ;      inclined     plane, 
637. 

—  Gran  jean's  lathe  for  cutting,  616. 

—  guide,  for  cutting  screws  with  change 

wheels,  625. 

—  heads  of,  Geneva  tool  for  polishing 

small,  1185;  screw  head  saw,  722  ; 
circular,  753. 

—  Healey's  apparatus  for  cutting,  618. 

—  Hindley's  tangent,  592. 

—  hobs,  591  ;  with  concentric  grooves, 

648  ;  proving  rounded  threads  of, 
629. 

—  HoltzapffePs    screw  threads,  their 

approximate  measures,  673. 

—  indenting,  or   squeezing,  for  vices, 

678. 


Screws,  irregular,  Mallet's  method  of  de- 
scribing on  blank  cylinders,  1010. 

—  irregularities,    detected    by   micro- 

scopic examination,  646  ;  various 
modes  of  correcting,  6 36, 646,  648, 
651. 

—  joiners',  Warren's  mode  of  casting, 

679  ;  Wright's  machine  for  cutting, 
608. 

—  Jones's  tap,  with  loose  cutters,  590. 

—  lathes   for  cutting,   Besson's,   616 ; 

Gran dj  can's,  616  ;  ordinary,  611; 
screw  mandrel,  612;  sliding-rest 
with  change  wheels,  621;  travers- 
ing rest,  624 ;  trains  of  wheels,  me- 
thods of  computing,  626  ;  Varley's 
apparatus,  620. 

—  left-hand,  cut  with  guide  screw  and 

change  wheels,  622  ;  originating 
from  right-hand  taps,  604 ; 
Walsh's  method,  605. 

—  long,  slender,  modes  of  cutting,  610. 

683. 

—  Mallet's  method   of  describing   re- 

gular or  irregular,  on  blank 
cylinders,  1010. 

—  Maudslay's    method    of    correcting 

length  of  guide  screws,  644  ; 
originating  with  inclined  knife, 
&c.,  641  ;  improvements  in  screw- 
ing tools  generally,  646. 

—  micrometer,  Allan's  method  of  cut- 

ting with  dies,  647  ;  Ross's,  648. 

—  microscopic   examination  of,    645  j 

scales  as  tests  of,  651. 

—  moulds    for    upholsterers'   fringes, 

method  of  cutting,  612. 
Screw  nuts,  cast  on,  580,  668. 

• —         divided,  or  split,   to   compensate 
for  wear,  663. 

—  elastic,  or  springing,  664. 

—  proportions  of,  663. 

—  tendency  of  angular    threads   to 

burst  the,  662. 

—  original,  comparative  perfection  of 

Donkin's  &  Maudslay's,  654. 

—  originating,    Allan's    method    with 

inclined  hollow  knife,  581. 

—  Barton's  method,  with   band   or 

chain,  645. 

—  Clement's,    methods    with   hobs, 

tools,  and  dies,  648. 

—  Donkin's  method  of,  and  improv- 

ing, 651. 

—  early  methods,  579,  635. 

—  fusee  engine,  with  inclined  plane, 

637. 

—  left-hand,  from  right-hand  taps, 

604. 

—  Maudslay's   methods,   581,    641  ; 

method  of  correcting  total 
length,  644  ;  applied  by  Mr. 
Donkin  to  minute  errors,  651. 


1463 


INDEX. VOLS.    I.    TO    III. 


Screw,  originating,  Plumier's  method,  579. 

—  Reid's  screw-engine,  with  inclined 

plane  for,  639. 

—  Ramsden's  engine,  640. 

—  Robinson's  method,  580. 

—  Troughton's    method    of    exami- 

nation, with  two  microscopes, 
645. 

—  Walsh's  method,  by  rolling  con- 

tact, 581. 

—  wires,  by,  coiled,  580;  soldered,  581. 
Screws,  Perkins's,  joints  for  cast-iron  pipes, 

580. 

—  pitch  of,   determines   power,    658  ; 

importance  of  agreement  in  screws 
and  nuts,  659. 

—  plates,  for  small  screws,  595. 

—  proportions,  arbitrary  characters  of, 

655  ;  tables  of,  670,  671. 

—  Rand's  compressed,  for  collapsible 

tubes  of  tin,  681. 

—  Ramsden's  engine  for  cutting,  640. 

—  Reid's   engine  with  inclined  plane, 

639. 

—  Roberts's    bolt-screwing    machine, 

608;  lathe,  633. 

—  Ross's    method   of  cutting    micro- 

meter, 648. 

—  rounded  threads,  629. 

—  Scott's,  joints  for  cast-iron  pipes, 

680. 

sections  of  taps,  longitudinal,  587  ; 
transverse,  584,  586. 

—  sections  of   threads,    665  ;    com- 

parative strengths  of  angular 
and  square,  656. 

—  slide-rest,  driven  by  bands,  627  ; 

by  change  wheels,  621. 

—  square  thread,  630  ;  comparison 

with  angular,  657,  662. 
'  —  strength  of,  656  ;  cohesive  strength 
of  the  bolt,  658  ;  of  the  hold 
derived  from  interplacement  of 
threads,  659  ;  comparison  of 
angular  and  square  threads,  657, 
662  ;  mechanical  power  of  the 
thread,  660  ;  relative  strength 
of  nuts  and  screws,  661. 

—  tables,  approximate  values  of  J.  J. 

Holtzapffel's  original  screw- 
threads,  673 ;  Chidson's  pro- 
portions of  small  screws  of  fine 
angular  threads,  671  ;  Whit- 
worth's,  for  angular  thread- 
screws  ;  relative  strengths  of 
different  sections  of  threads, 
657. 

—  tangent,  668  jHindley's  curved,  592. 
tapping,   cast-iron,    587  ;    distant 

holes,  589  ;  pipes  for  gas  or 
water,  1004  ;  shallow,  and 
thoroughfare  holes,  588  ;  works 
in  the  lathe,  590. 


Screw   taps,  for    cutting    internal  screws, 

583. 

Bodmer's  patent,  585. 
brace  for  driving  small,  589. 
chamfering,  or  relieving,  586. 
fluted,  585. 
half-round,  584. 
handles  for,  589. 
Jones'  cutters  for,  590. 
master,  or   original,  591  ;  pro- 
portions of,  600. 

—  Maudslay's     improvement     in, 

646. 

plug,  589  ;  regulating  dies  for, 
676. 

sections  of,  longitudinal,  587  ; 
transverse,  584. 

square,  583. 

taper,  589. 

triangular,  583. 

wood  screws,  for,  592. 

wrenches,  589. 

Screw    threads,  angular,  rounded,  square, 
and  others  compared,  666. 

considered  in  respect  to  their 
forms,  proportions  and  general 
characters,  655. 

double  and  treble,  cut  with  guide 
screw  and  change  wheels,  622. 

Holtzapffel's,  approximate  mea- 
sures of,  673. 

left-hand,  cut  with  guide  screw 
and  change  wheels,  622  ;  origi- 
nating from  right-hand  taps, 
604  ;  Walsh's  method,  605. 

—  sections  of  different  forms,  666. 
Screw   tools,   or    chasing    tools    used    by 

hand,  applications  of,  611; 
for  hard  wood,  520  ;  soft  wood, 
516. 

cutters  or  hobs  for  making,  591. 
fixed,  for  traversing  lathes, 
angular,  628  ;  rounded,  629  ; 
square,  630  ;  adjusting  pene- 
tration of,  633  ;  Bodmer's 
and  Clement's,  629  ;  Holt- 
zapffel's cutter-bar  for  square 
threads,  631  ;  Shank's  arrange- 
ment of  two  tools,  633  ;  tra- 
versing the  tools  backwards, 
632. 
revolving,  for  internal  screws, 

569,  631. 

Screws,    Troughton's  method  of  examina- 
tion with  two  microscopes,  645. 

—  uniformity  of,  arbitrary  measures 

generally  adopted,  and  incon- 
veniences resulting  therefrom, 
669. 

—  agreement  with  standard  measure 

desirable,  692. 

change  of  system,  inconvenience 
of,  672. 


INDEX. VOL8.    I.    TO    III. 


1464 


Screws,  uniformity  of,  Chidson's  table  for 

small  screws,  671. 
difficulties  attending  adoption  of, 

672. 
methods  commonly  adopted  to 

obtain,  676. 
principally    desirable  in  large, 

677. 
standard    gages,   difficulties    of 

maintaining,  675. 
variety  of  threads  required  for 

every  size,  674. 
Whitworth's   proposed   system, 

670. 
written  measures,  advantages  of, 

677. 
3ws,    Varley's      lathe     apparatus,    for 

cutting,  620. 

Walsh's  method  of  originating  left- 
hand,  605. 
Warren's  method  of  casting,  for 

presses  and  vices,  679. 
wheels,    in    Piedmont  silk   mills, 
668  ;   tangent,  668  ;  Hindley's, 
592. 

Whitworth's   screw    stocks,   605, 
609  ;  system  of  screw  threads, 
670. 
Wilk's    method    of    casting,   for 

presses  and  vices,  679. 
wood,  chasing  tools  for,  516,  520, 

611  ;  cut  with  screw  box,  593. 
worm-wheel  cutter,  592. 
Wright's    machine     for     cutting 

joiners,  608. 

ilpture,  rifflers  used  for,  837  ;  smoothing 
and  polishing,  1077. 
Sea-cow  teeth,  1 39. 
Sea-ear  shells,  120. 
Sea-horse  teeth,  138. 
Seal  engraving.     See  ENGRAVING,  GEM  and 

SEAL. 

Seal  handles,  cutting  in  carnelian,  &c.,  1318. 
Sealing-wax  varnish,  1398. 
Seam-set,  for  joining  sheet  metals,  387. 
Seasoning,  ivory,  152  ;  wood,  23. 
Sea-unicorn  teeth,  139. 
Seddons,  Mr.,  on  woods,  65. 
Seerig,  A.  W.  H.,  on  surgical  saws,  801. 
Serpentine,  166  ;  polishing,  1093. 
Service-tree  wood,  106. 
Setting   razors,   introductory   remarks  on, 

1146  ;  practice  of,  1153. 
—       saws,   with    hammer,   696  ;  pliers, 
and  saw  set,    697;   circular    saws, 
698. 

Shadbolt,  Mr.,  on  woods,  65. 
Shank,  used  by  iron  founders,  369. 
Shanking,   or   "nibbling,"   glass   disks   for 

lenses,  1265. 

Shanks,  Mr.  A.,  differential  screw  drill,  562  ; 
sliding-rest  for  cutting  screws  with  two 
tools,  633. 


Shaping  machine,  for  arbitrary  forms   in 

metal,  901. 
Sharpening,  angular  tools  for  ornamental 

turning,  1162,  1164. 
bead  tools  and  drills,  1 1 70. 
chisels,  paring,  1144  ;  turning, 

1 1 4-). 
concave  edges  of  tools,  upon 

conical  grinders,  1170. 
cutting     tools,     on      artificial 

grinders,  1156. 

cutting  tools,  on  the  oilstone, 
1141. 

—  drills    and    revolving    cutters 

for  ornamental  turning,  1167, 
1173. 

floats,  838. 

gouges,  cabinet-makers,  1144  ; 
turning,  1145. 

guides,  for  setting  tools  to  de- 
finite angles,  1158. 

instruments  for  angular  and 
straight  tools,  for  ornamental 
turning,  1162,  1164. 

—  instrument  for  bead  drills  and 

tools,  1172. 

instrument  for  ordinary  turn- 
ing tools,  with  rectilinear 
edges,  1159. 

moulding  plane-irons,  1145. 

moulding  tools  for  turning,  520 
1170,1176. 

plane-irons,  496,  1144. 

—  punches    with    cutting   edges, 

1177. 

razors,  general  view  of  the  pro- 
portions and  sections  of, 
1 1 46  ;  good  and  faulty  con- 
ditions of  the  edge  ;  tests 
for  keenness,  1150;  setting 
on  hone,  and  use  of  the  strop, 
1153;  Sir  J.  Robison's  in- 
strument for,  1177. 

saws.     See  SAWS,  SHARPENING. 

—  scissors,  909. 

screw  tools,  250,  1141. 
slide-rest  tools,  for  ornamental 
turning,    1162,   1164,  1170, 
1176. 

slide-rest  tools  for  plain  turn- 
ing, 530. 
turning  tools,  used  by  hand, 

1145. 

Shearing   curvilinear  works,   with   cutting 
chisels,   918;    with  punching    machines, 
950. 
Shearing  machines,  Barton's  double,  920. 

—  brads  and  cut  nails,  for,  948. 

—  engineers',  for  metal,  919. 

—  hydraulic,  for  cutting  off  copper 

bolts,  924. 

—  Nasmyth,    Gaskell,  and    Co.'s, 

for  wide  boiler  plates,  923. 


1465 


INDEX. VOLS.    I.    TO    III. 


Shearing  machines,  Robert's  bar-cutting,  923 ; 
lever,  for  boiler  plates,  920; 
portable,  with  slides,  921. 

—  rotary,  for    grass   lawns,   914  ; 

nail-rods  and  thin  plates,  188, 
925;  woollen  cloth,  913. 

—  stationers',     for    ruling     pens, 

918. 

—  Thorneycroft's,  for  wide  plates, 

923. 

Shears,  action  of,  and  general  observations 
on,  904. 

—  averruncator,  for  pruning,  912. 

—  bench,  for  metal,  915. 

—  card-makers',  912. 

—  Collett's,  for  tags  of  laces,  918. 

—  cutting  nippers,  905. 

—  engineers',    generally   worked    by 

steam  power,  919. 

—  garden,  911. 

—  hand,  for  metal,  915. 

—  perpetual,  for  woollen  cloth,  913. 

—  printers',  917. 

—  pruning,  911. 

—  purchase,   for    thick    sheet  metal, 

916.     ' 

—  revolving,  913,  925. 

—  scissors,  907. 

—  sheep,  909. 

Shear  steel,  manufacture  of,  192. 
Sheet-glass,  manufacture  of,  122  3 ;  machines 

for  grinding,  1224  ;  polishing,  1225. 
Sheet-metal  works  : — 

—  annealing  sheet-iron,  976. 

—  anvils,     stakes,     and     teests    for, 

386. 

—  beak  irons,  for,  387. 

—  bending,  377. 

angles  of,  387. 

—  conical,  382. 
curved,  383. 

cylindrical,  with  former,  389 ; 

moulds,  388  ;  rollers,  389. 
folded,  with  plane  surfaces,  380. 
scale,  for  setting  out  polygonal, 

384. 

—  Birmingham  gage  for,  1015. 

—  chasing,  413. 

circular,  spun  in  the  lathe,  395. 

—  conical,    made   by  bending,   382  ; 

raising,  398  ;  spinning,  395. 

—  creasing  tools,  for,  387. 

—  curved,   made    by   bending,   383  ; 

raising,  398  ;  spinning,  395. 

—  flattening,  the  principles  and  prac- 

tice   of,    thin    plates    with    the 
hammer,  414. 

—  flattening,  with  rollers,  390. 

—  former,  for  bending  tinned  plate, 

38.9. 

—  Foxall's  patent  method  of  raising, 

by  alternate  spinning  and  stamp- 
ing, 974. 


Sheet  metal  works,  gages  at  present  used  for 
measuring  the  thicknesses  of,  and 
proposals  for  a  new  system  of 
gages  founded  on  the  decimal 
subdivision  of  the  inch,  1011. 

—  hammers  'for,  385  ;    covered   with 

cloth,  411  ;  effects  of  hollow  and 
solid  blows,  399. 

—  joining,  made  by,  376. 

—  joints,  angle;  butt,  lap,  and  mitre, 

391 ;  bolted,  folded,  keyed,  and 
riveted,  392. 

—  joints,   surface;   butt,  cramp,   and 

lap,   393  ;  crease,  hollow,  over- 
lap, and  riveted,  394. 

—  Larivier's  method   of  perforating, 

943. 

—  pitch  block,  for  chasing,  413. 

—  planishing,  plated,  412. 
— -      punches  for,  387,  943. 

—  raising,  395. 

ball  and  cross  of  St.  Paul's  cathe- 
dral, 405. 

—  chasing,  413. 
complex  works,  407. 
French  horn,  407. 

Foxall's  patent  method  of,  by 
alternate  spinning  and  stamp- 
ing, 974. 

—  hemispheres,  402. 

—  jelly  moulds,  408. 

—  malleability  of  metal,  398. 

—  ornamental  works   by   stamping, 

409. 

—  planishing  plated  works,  411. 

—  proportioning    metal   to    object, 

398. 
reversing,  412. 

—  snarling,  412. 

—  spinning  circular  works,  395. 

—  stamping    shallow    works     with 

dies,  409. 
— .          thimbles,  410. 

tools,  peculiarities  in,  410. 

—  vases,  &c.,  466. 

—  Roberta's  machine,  for  bending  and 

flattening,  390. 

—  seam  set  for,  387. 

—  soldering,  445. 

—  spinning,  395. 

—  stamping,  409. 

—  swage  tool  for,  387. 

—  tinmen's  bending  rollers  for,  389. 

—  tools  for,  385,  410. 
Shell,  bits  for  boring  wood,  539. 

—  cameos,  carving,  1094. 

—  grinding,  for  lenses,  1263. 

—  pearl-shell,  119  ;  polishing,  1094. 

—  tortoise-shell,    general     methods    of 

working,  126  ;  polishing,  1099. 

—  turtle-shell,  127,  1101. 

Shells,  nacreous  and  porcellaneous,  117. 

—  polishing,  1093. 


INDEX. VOLS.    I.    TO    III. 


1466 


Ship  building,  timber  for,  22,  69. 
Shooting  boards,  applications  of,  502,  835. 
Siberian  fossil  ivory,  138. 
Side,  fillister  plane,  485. 

-  rebate  plane,  489. 

—  hatchet,  action  of,  472. 

-  tools  for  turning,  metal,  983  ;  wood, 

516,  518. 

Sieves  for  emery  powder,  1 054. 
Silcock  &  Lowe,  Messrs.,  patent  planes  for 

joiners,  978. 

Silex,   base   of  several   polishing  powders, 
'    1029,  1097. 

Silk  polisher,  for  lenses,  1270. 
Silver,  general  character,  uses  and  alloys  of, 
282  ;  cohesive  force  of,  288. 

—  amalgam    of,   used   by   dentists  for 

stopping  teeth,  970. 

—  German,  composition  of,  279. 

—  solders,  283. 

Silversmiths'  work,  bench  for,  731 ;  pierc- 
ing, 730  ;  polishing,  1097. 
Sissoo  wood  (Dalbergia  smoo),  106. 
Size  for  varnished  works,  1403. 
Skive  for  polishing  diamonds,  1097. 
Slate  billiard  tables,  57. 

—  general  mode  of  working,  1 65. 

—  moulds,  for  casting,  engraved  in  in- 

taglio, 166. 

-  polishing,  for  metal  works,   analysis 

of,  1 029. 

—  polishing  works  of,  1097. 

—  sawing,  816. 

Slicer,  or  slitting  mill,  for  lapidary  work, 

1098,  1307. 

Slide  lathe,  with  change  wheels  for  screw- 
cutting,  624. 

—  clasp  nuts  for  traversing  rest  back- 

ward, 632. 

—  divided  nuts  to  compensate  for  wear, 

663. 

—  Roberts's  arrangement  for  travers- 

ing tool  backwards,  633. 

—  Shank's     arrangement     with      two 

tools,  633. 

Slide-rest,  with  change  wheels  for   screw- 
cutting,  621. 

—  tools.     See  TURNING  TOOLS. 
Slitting  mill,  for  lapidary  work,  1098,  1307. 
Slotting  machine,  for  cutting  mortises,  &c., 

in  metal,  900. 

Smart,  Mr.,  combination  of  two  circular 
saws  for  cutting  tenons,  794  ;  curved 
guide  for  cutting  staves  of  casks,  804  ; 
parallel  guide  for  cutting  straight  works 
from  irregular  pieces,  792. 
Smith,  Mr.,  method  of  imitating  granulation 

of  skin  on  sculptured  works,  1078. 
Smith's,  screw-head  saw,  722. 

frame  saw,  729  ;  sharpening,  691. 
plane,  483,  867. 
Smoothing  plane,  478. 
Snake-stone,  for  polishing,  1065. 


Snake  wood,  106  ;  thickness  of  sap,  21. 
Snarling   iron,  for  raising   deep  works  in 

sheet  metal,  412. 
Snuffers,  case-hardening,  261. 
Soap  and  water,  proposed  by  Mr.  Reveley 

to  be  used  instead  of  oil  for  setting  razors, 

&c.,  1098. 
Soap-stone,  1098. 
Softening  cast  iron,  259. 

—  horn,  123,  126. 

—  ivory,  153. 

—  steel,  238. 

—  tortoiseshell,  128. 

—  whalebone,  136. 

—  wood,  26,  32. 
Soldering,  general  remarks  on,  432. 

—  autogenous,  454. 

—  binding   wire  for  fixing    works, 

443  ;  clay  props  employed  by 
Asiatics  as  substitutes,  977. 

—  blow-pipe,    general    applications 

and  forms  of,  437,  449  ;  airo- 
hydrogen,  454  ;  bellows  and  gas 
flame,  439  ;  table  and  work- 
shop, 440. 

—  brass,  442  ;  by  burning,  452. 

—  brazing,  brass  and  copper,  442  ; 

iron,  443. 

—  burning   together,   or   soldering, 

per  se,  452. 

—  cast  iron,  by  burning,  452. 

—  cleanliness,  importance   of,   441, 

444. 

—  compensation  balance,  for  chro- 

nometers, 453. 

—  copper,  442,  447. 

—  copper-bits,  for  445,  447. 

—  fluxes,  generally  used,  435 ;  borax, 

442  ;  gallipoli  oil,  450  ;  muriate 
of  zinc,  447  ;  resin,  446  j  sal- 
ammoniac,  447. 

—  fuel  for,  437. 

—  gas-pipes,  449. 

—  gold  and  silver  works,  444. 

—  hard,  general  remarks  on,  441. 

—  heat,   modes  of    applying,    435  ; 

blow-pipe,  airo-hydrogen,  455  ; 
blowpipe,  ordinary,  438  449, 
462  ;  copper  bit,  447,  455  ; 
furnace  and  hearth,  436. 

—  iron,  for,  445. 

—  iron  and  steelworks,  443. 

—  jewellery,  444. 

—  lamps  used  with  blow-pipes,  439. 

—  large  works  by  burning,  452. 

—  lead,  autogenous   process,    455  ; 

burning,  452  ;  plumber's  me- 
thod, 445. 

—  per  se,  or  burning  together,  452. 

—  pewter  works,  449  ;  by  burning, 

452. 

—  silver,  443. 

—  small  works  with  silver  solder,  443. 


1467 


INDEX. — VOLS.     I.    TO    III. 


Soldering,  soft,  general  remarks  on,  444. 

—  steel,  443  ;  by  burning,  453. 

—  supports  for  small  works,  char- 

coal, 444  ;  pumice-stone,  978  ; 
wire,  439. 

—  tabular  view  of  the  process   of, 

434. 
thick  works,  447. 

—  thin  works,  445. 

—  tinned  plate,  446. 

—  tinning  thick  pieces,  447. 

—  tortoiseshell,  128. 

—  tubes,   brass    and    copper,   442; 

lead  and  tin,  449,  462. 

—  zinc,  447. 

Solders,  fusibility  of,  285,  303,  435. 

—  gold,  27  6. 

—  hard,  268,  432,  434,  441. 

—  lead,  435. 

—  oxidation  of ;  inconveniences  caused 

by,  452. 

—  pewterers',  266,  450. 

—  plumbers',  285. 
_       silver,  283,  443. 

_       soft,  266,  285,  434,  444. 

—  spelter,  268. 

—  tin,  285,  435. 

—  white,  for  buttons,  273. 
Sommering's  method   of  concentrating  al- 
cohol, 1379. 

Spanish  chestnut,  wood.     See  CHESTNUT,  80 . 
Spanish  mahogany.     See  MAHOGANY,  91. 
Speckled  wood.     See  SNAKEWOOD,  106. 
Spectacle  frames  of  tortoiseshell,  130. 
Specula,  backs  for  supporting,  1275,  1288. 
• —       bed  of  hones  for  smoothing,  1276. 

—  casting,  371,  462. 

—  Edwards',   Rev.  J.,   grinder   and 

polisher  for,  1276. 

—  Greene,  Dr.  R.,  machine  for  grind- 

ing and  polishing,  1292. 

—  grinding,  by  hand,  1275  ;  by  ma- 

chinery, 1280. 

—  Hodgson's,  Rev.  W.,  machine   for 

grinding  and  polishing,  1293. 

—  Lassell's,   Mr.    W.,   machine    for 

polishing,  1289. 

—  polishers      for,     Mr.     Edwards's, 

1278  ;  Mr.  Lassell's,  1292  ;  Earl 
Rosse's,  1284. 

—  polishing,  by  hand,  1279  ;  by  ma- 

chinery, 1282, 1289, 1292, 1293. 

—  polishing,  plane  specula,  1231. 
polishing,   six-foot  speculum ;   at- 
mosphere influences,  1 287. 

Rosse,  Earl,  casting,  371;  six-foot, 
462  ;  composition  of  metal  for, 
270  ;  Ed  wards' elliptical  polisher 
for,  1278  ;  machine  for  grind- 
ing and  polishing,  three-foot, 
1280  ;  six-foot,  1286  ;  mould  for 
casting,  371  ;  polishing  plane, 
1231. 


Specular  iron  ore,  preparation  of,  for  polish- 
ing, 1083. 

Speculum  metal,  composition  of,  270. 

Spelter.     See  ZINC,  285. 

Spelter  solder,  268. 

Spindle-tree  wood  (Euonymus  europea};107. 

Spinning,  thin  circular  works  in  sheet  metal 
as  rings,  tea-pots,  &c.,  395. 

Spirit  of  turpentine,  qualities  of,  as  a  vehicle 
for  varnishes,  1378. 

Spirit  of  wine,  qualities  of,  as  a  vehicle  for 
varnishes,  1378  ;  concentrating,  1379. 

Spirit  varnishes,  general  instructions  for 
making,  1388. 

Spheres,  Mr.  Guy's  method  of  grinding  accu- 
rate, 1257. 

Spherical  surfaces,  production  of,  by  abra- 
sion. See  GRINDING,  LENSES,  and  SPECULA. 

Spherometer,  for  measuring  curvature  of 
lenses,  1271. 

Splitting,  splints,  for  chemical  matches,  982; 
staves  for  casks,  32  ;  veneers,  805, 

Spokeshave,  479. 

Spoon-bits,  for  boring  wood,  539. 

Springs,  hardening  and  tempering,  250. 

Square,  application  of,  in  filing  metal,  880  ; 
planing  wood,  501. 

Stag-horn,  121  ;  straightening,  957. 

Staining,  horn,  126  ;  woods,  growing,  43  ; 
with  lime-water,  44. 

Stakes,  anvils,  and  teests  for  working  sheet 
metals,  386. 

Stamped  works  in  brass,  annealing,  and 
pickling,  1410  ;  dipping  and  bronzing, 
1411. 

Stamping  thin  sheet-metal  works,  409,  974. 

Statuary,  smoothing  and  polishing,  1077. 

Statues,  ancient,  in  ivory,  140. 

Statues,  metal,  moulding  and  casting,  365. 

Steatite,  166  ;  polishing,  1098. 

Steel,  analysis  of,  236. 

—  annealing,   effects   of  different  treat- 

ment, 238  ;  plates  for  transfer  en- 
graving, 254  ;  rapidly,  by  inter- 
mittent cooling,  242. 

—  blister,  manufacture  of,  191. 

—  burnishers',  action  and  application  of, 

1042. 

—  case-hardening,  254  ;   with  prussiate 

of  potash,  262. 

—  cast,  manufacture  of,  1 92. 

—  cementation  of,  191  ;  compared  with 

case-hardening,  263  ;  Macintosh's 
process,  263. 

—  cohesive  force  of,  284. 

—  compared  with  glass,  237. 

—  decarbonizing,  238. 

—  engraved  buttons,  showing  prismatic 

colours,  42,  646. 

—  forging.     See  FORGING. 

—  fracture  of,  index  of  quality,  193. 

—  hammering,  improves  quality  of,  1! 

—  hardening.     See  HARDENING. 


INDEX. VOLS.    I.    TO    III. 


1468 


Steel,  manufacture  of,  191. 

—  qualities  of,    judged  of  by  fracture, 

193. 

-  restoring,  when  overheated,  230. 

—  softening,  238. 

-  tempering.     See  TEMPERING. 

—  welding  to  iron,  228. 
Stereotype  founding,  325. 

Stivens,  Mr.,  expanding  lathe  drill,  1008. 
Stodart,  Mr.,  on  hardening  steel,  243  ;  table 

of  temperature  for  tempering  steel,  245. 
Stops  for  planing  benches,  494,  980. 
Stone,   Mr.   J.,   expanding    center-bit    for 

wood,  542 
Stone,  saws  for  soft,  1189  ;  for  hard,  1190, 

1195. 
Stone,  working.     See  LAPIDARY-WORK,  and 

MARBLE. 

Straggling,  or  ragging,  grindstones,  1 1 09. 
Straight-edge,  application  of,  in  filing  metal, 

865  ;  in  planing  wood,  499. 
Straight-edges,  instructions  for  originating, 

in  wood  and  metal,  873. 
Straightening,  cylindrical  shafts,  426. 
sheet  metals,  399. 
stag  horn,  957. 
wires,  424. 
Straker's   mode   of    imitating   carvings  in 

wood,  46. 

Strickle,  used  in  moulding  pipes,  363. 
"Strops  for  razors,  1155. 
Surface  plates,  application  of,  in  filing  flat 
surfaces,  866. 

—       general  forms  of,  and  instructions 

for  originating,  875. 
Surgical,  cutting  nippers,  906. 

saws,  800. 
—       scissors,  911. 
Sutherland,  Col.  Sir  J.,  on  woods,  65,  97. 
Swage-block  and  tools,  for  forging,  214,231, 

233. 

Swage-tool,  for  sheet-metal  works,  387. 
Sycamore-wood  (Acerpseudo-platanus),  107. 
Sykes,  Col.,  on  woods,  65,  97. 
Symonds,  Sir  W.,  Admiralty  museum   of 

woods,  68. 
Szentepeteri's  specimen  of  chasing  in  alto 

relievo,  414. 


T. 


CABLE,  compass  and  lock  saws,  711. 
Tables  of  :— 

Analyses  of  grinding  and  polishing  ma- 
terials, 1029. 

Birmingham  and  Lancashire  sheet- 
metal  and  wire  gages,  with  values  of, 
expressed  in  decimal  parts  of  the 
inch,  1013. 

Cohesive  force  of  alloys,  289  ;  solid 
bodies,  287  ; 

Cutting  angles  of  planing  and  turning 
tools,  by  Rev.  Professor  Willis,  994. 


Tables  of : — 

Decimal  proportions,    converting   into 
divisions  of  the  pound  avoirdupois, 
1024. 
Divisions  of  circle,  in  instrument  for 

cutting  facets,  1345. 
Hardness  of  minerals,  158. 
Heats  for  tempering  steel,  245. 
Planes,  proportions  of,  474. 
Rod-iron    gauge,   Bradley   and   Co.'s, 

1016. 
Saws,   proportions  of,    circular,  784  ; 

rectilinear,  699. 

Screws,  proportions  of  angular  thread 

screws,  Chidson's,  671 ;  Whitworth's, 

670  ;   relative  strengths  of  different 

sections  of  threads,  657. 

Tubes,    synopsis    of   manufacture    of 

wrought  iron,  964. 
Wire  gages,  1014. 

Woods  principally  used  in  England,  70. 
Tabular  view  of  processes  of  soldering,  434. 
—         some  of  the  properties   of  me- 
tals,    viz.  brittleness,  chemi- 
cal equivalents,  ductility,  fusi- 
bility, hardness,  linear,  dila- 
tions   by    heat,   malleability, 
power    of    conducting    heat, 
and  specific  gravity,  290. 
Tangent  screw,  668  ;  Hindley's  curved,  592. 
Tapping,  cast-iron,  587;  distant  holes,  589  ; 
pipes  for  gas  or  water,  1004  ;  shallow  and 
thoroughfare  holes,   588  ;    works  in  the 
lathe,  590. 
Taps  for  cutting  internal  screws,  583. 

—  Bodmer's  patent,  585. 

—  brace  for  driving  small,  589. 

—  chamfering  or  relieving,  586. 

—  fluted,  585. 

—  half  round,  584. 

—  handles  for,  589. 

—  Jones's  cutters  for,  590. 

—  Master  or  original,  591  ;    proportions 

of,  600. 

—  Maudslay's  improvements  in,  646. 

—  plug,  589  ;  regulating  dies  for,  676. 

—  sections  of,  longitudinal,  587  ;    trans- 

verse, 584. 

—  square,  583. 

—  taper,  589. 

—  triangular,  583. 

—  wood  screws,  for,  592. 

—  wrenches  for,  589. 

Taylor's  patent  for  making  casks,  32. 
Teak-wood  (Tectona  grandis),  107  ;  shrink- 
age of,  47. 

Tedge,  in  pewterer's  moulds,  321. 
Telescope.     See  LENSES  and  SPECULA. 

—         tubes,  blacking  interior  of,  1398  ; 

covering  with  whale-bone,  136; 

polishing  brass,  1039. 
Templets,  applications  of,  in  filing,  890. 
Tempering  "  blazing  off,"  250. 


1469 


INDEX. VOLS.    I.     TO    III. 


Tempering, colouring  watch-springs,  251. 
gun-lock  springs,  250. 

—  heats  for,  245. 

—  oily  mixtures  for,  249. 

—  steel,  235.  See  also  HARDENING. 

—  tortoiseshell,  128. 

Tenon  and  mortise  joints  in  wood,  56,  715.. 

—  saws,  713. 
Tenons,  sawing,  717. 

Tetrahedron,    cutting    with    circular    saw, 

774. 

Thericles,  celebrated  for  turning,  5. 
Thimbles,  raising  by  stamping,  410. 
Thiout's,  method  of  cutting  the  teeth  of  files 

by  machinery,  840  ;  old  fusee  engine  with 

change  wheels,  618. 
Thorneycroft's  shearing  machine  for  wide 

plates  of  iron,  923. 
Thurston,  Mr.,  on  billiard  tables,  57. 
Timber.     See  WOOD. 
Timperlay's  process  of  Kyanising  timber, 

22. 

Tin,  general  characters,  uses,  and  alloys  of, 
283. 

—  bearings  for  machinery,  322,  970. 

—  cohesive  force  of,  288 ;  alloys,  289, 297. 

—  foil,  manufacture  of,  283. 

—  polishing  works  in,  1099. 

—  solders,  composition  of,  285. 
Tinning,  cold,  301,  451. 

—  iron  plates,  284  ;    Morewood  and 

Rogers's  galvanic  process,  972. 

—  metal  works  generally,  450. 

—  thick  works  for  soldering,  447. 
Tomes,  Mr.,  patent  dentifactor  for  making 

artificial  gums,  palates,  and  teeth,  955. 
Tongs,  forging,  200  ;  pin,  862  ;  sliding,  862. 
Tools,  boring.     See  BORING  TOOLS. 

—  cutting,  angles   and  positions   of,    as 

regards  the  act  of  cutting ;  division 
into  paring,  scraping,  and  shear- 
ing ;  angles  of  edges  suited  to 
different  materials  and  general 
mode  of  action,  458—463. 

—  forms  and  motions  of  tools  as  re- 

gards the  production  of  lines, 
superficies  and  solids,  theoreti- 
cally considered,  463 — 467. 

—  general  principles  of  their  action, 

comparison  of  cutting  and  split- 
ting, 472. 

—  guide,  principle,  its  application  both 

in  manual  and  machine  processes, 
468—471. 

—  lubrication  and  velocity  of,  470. 

—  filing.     See  FILES. 

—  grinding.     See  GRINDING. 

—  punching.     See  PUNCHES. 
sawing.     See  SAWS. 

—  screw  cutting.     See  SCREW. 

—  shearing.     See  SHEARS. 

—  turning.     See  TURNING  TOOLS. 
Toon-wood  (Cedrela  To&na),  108, 


Toothing  plane  for  veneers,  61,  483. 
Topaz,  173,  1099. 
Tortoiseshell,  126. 

boxes,    moulded,    131  ;    ve- 
neered, 133. 

combs,  parting,  130. 

factitious,  155. 

frames,   for    eye-glasses    and 
spectacles,  130. 

inlaying,  134. 

—  joining,  128,  130. 
moulding,  131. 

—  .       polishers  for  watch- work,l  040. 

polishing,  1099. 

—  softening  and  soldering,  128, 

130. 

tempering,  128. 
Touchstone,  1100. 
Toy-maker's  paring-knife,  26. 
Trapezohedra,  cut  with  the   circular   saw, 

777. 
Tredgold,  on  cedar  of  Lebanon,  79;  tables  of 

cohesive  force  of  solid  bodies,  286. 
Treenails,  methods  of  compressing,  29. 
Trent  sand,  for  polishing,  1091. 
Trephine  saws,  800. 
Triblets,  for  drawing  metal  tubes,  429. 
Tripoli,   analysis  of,  1029;   preparation  of, 

for  polishing,  1084,  1100. 
Trotter,  Mr.,  spherical  saw  for  curvilinear 

sawing,  803. 
Troughton's  method  of  examining  screws 

with  two  microscopes,  645. 
Tubal  Cain,  supposed  by  Plumier  to  have 

practised  turning,  4. 

Tubes,  drawing  metal,  429;  lead  and  tin, 
431;  square,  430;  taper,  976. 

—  forging  iron,  225;  Prosser's  rever- 

beratory  furnace  for,  969. 

—  iron,  synoptical  table  of  the  manu- 

facture of  wrought-iron  tubes, 
followed  by  brief  professional 
notices  of  the  several  patents, 
963—968. 

—  Rand's  collapsible  tin,  drawing,  431 ; 

raising  by  fly  press,  977. 

—  soldering,  442. 

Tugmutton  wood.     See  BOX-WOOD,  76. 
Tulip-wood,  108. 

Tulloch,  Mr.  James,  machines  for  grinding 
flat  surfaces  on  marble  slabs,  1211;  for 
sawing  marble  slabs,  1203;  feed  appa- 
ratus for  supplying  sand  and  water, 
1205. 
Turpentine,  oil  of,  its  qualities  as  a  vehicle 

for  varnishes,  1378. 
varnishes,  general  instructions 

for  making,  1388,  1397. 
Turquoise,  1101. 

Turrell,  Mr.,  on  working  diamonds,  176. 
Turtleshell.     See  TORTOISESHELL,  1099. 
Turners,  amateur,  different  pursuits  of,  10. 
—      anciently  called  vascularii,  5. 


INDEX. VOLS.    I.    TO    III. 


1470 


Turnery  woods,  preparation  of,  25 ;  sections 
of,  49;  shrinkage  of,  48:  table  of  those 
commonly  used  in  England,  70 ;  variations 
of  colour,  43. 

Turning  alabaster,  164. 

—  antiquity  of,  4. 

—  authors  on,  4 — 3. 

—  amber,  161. 
ascribed  to  Daedalus,  5. 

—  brass,  521. 

—  cannel  coal,  163. 
centering  blocks  of  ivory,  149. 

—  clay,  160-. 

—  cores  for  loam  moulds,  362. 
cylindrical  works  with  the  chisel, 

515;   gouge,  513;  graver,  523; 
heel  and  nail  head  tools,  526. 

—  diamonds,  180. 

—  egg  shells  for  vases,  155. 

—  facility  of,  compared  with  joinery, 

508—510. 

—  flat  surfaces,  with  the  chisel,  515  ; 

gouge,  514. 

—  fluor  spar,  168. 

—  freestones,  169. 

—  general  employment  of,  in  the  arts,  3. 
grindstones,  1108. 

—  hardened  steel,  179. 

hollow  works,  with  the  gouge  and 
hook  tools,  514. 

—  horn,  123. 

—  iron,  523. 

ivoi-y,  blocks,  149;  rings,  tubes,  &c., 
151. 

—  jewels,  with  diamond  tools,  179. 

—  loam  moulds,  for  bells,  363  ;  cylin- 

ders, 360  ;  pans  and  pipes,  &c., 
362. 

—  marble,  167. 

—  mosaic  works  in  wood,  766. 

—  polishing,  brass  works,  1038  ;  iron, 

1072;  wood,  1123. 

—  porphyry, 171. 

—  rings,  from  ivory  tusks,  151. 

—  rubies,  and  similar  hard  stones,  179. 

—  sandstones,  169. 

—  satin  stone,  1 64. 

—  screws  by  hand  in  common  lathes, 

611;  in   screw   mandrel    lathes, 
614. 

—  screws  by  machinery.     See  SCREW. 
Turning  tools  : — 

General  remarks  on,  508 — 512. 

Alabaster,  for,  164. 

Arm  rest,  522. 

Astragal,  519. 

Bead,  519  ;  grinding  and  sharpening, 
1170. 

Brass,  for,  520—523. 

Broads  for  soft  wood,  515. 

Cannel  coal,  for,  163. 

Chisel,  512  ;  grinding,  1138  ;  sharpen- 
ing, 1145. 


Turning  tools  : — 

Copper,  for,  537. 

Cranked,  for  iron,  526. 

Diamond,  179,  538. 

Flat,  518  ;  grinding,  1139. 

Gouge,  512  ;  grinding,  1139;  sharpen- 
ing, 1145. 

Graver  for  iron  and  steel,  523 :  grind- 
ing,  1140. 

Grinding,  1138,  1141. 

Hanging,  for  iron,  526. 

Hardwood  and  ivory,  for,  517 — 520. 

Heel,  for  iron,  525  ;  grinding,  1140. 

Hook,  for  iron,  525  ;  for  soft  wood,  514. 

Inside,  520  ;  parting,  519. 

Iron  and  steel,  for,  523—527. 

Left  side,  518  ;  grinding,  1139. 

Lubricating,  538,  983. 

Marble,  for,  167. 

Moulding  tools,  519  ;  grinding,  1141. 

Nail  head,  for  iron,  526. 

Parting,  for  hard  wood,  518  ;  ivory, 
151  ;  soft  wood,  517. 

Planishing,  for  brass,  522. 

Point,  for  hard  wood,  518  ;  grinding, 
1140  ;  marble  and  stone,  167. 

Profile,  519. 

Quarter  hollow,  and  quarter  round. 
519. 

Right  side,  518  ;  grinding,  1139. 

Round,  519  ;  grinding,  1140. 

Satin  stone,  for,  1 64. 

Side,  516. 

Screw,  516,  520  ;  application  of,  611  ; 
grinding,  1141. 

Sharpening  on  the  oil-stone,  1 1 45. 

Soft  wood,  for,  512—517. 

Square,  for  brass. 

Triangular,  for  iron,  523  ;  grinding, 
1140. 

Slide  rest  tools,  general  remarks  on, 
527,  531,  984,  992. 

—  Babbage,  C,.  Esq.,  cutter  bars  and 

tool  holders,  998;  face  cutter, 
991  ;  paper  on  the  principles  of 
tools  for  turning  and  planing, 
984. 

—  Bodmer's  patent  chasing  tool  for 

screws,  629. 

—  brass,  for,  530;  finishing  or  spring- 

ing, 536. 

—  Brunei's  cutter  bar,  535. 

—  Clement's,     chasing,     for     screw 

threads,  629 ;  finishing,  for  brass 
and  iron,  537. 

—  cylindrical  cutter^  for  iron,  535. 

—  eye  shade,  988. 

—  flexure  in,  effects  of,  533. 

—  grinding,  533,  983,  1141. 

—  hard  wood  and  ivory,  for,  530. 

—  Hotzapffel'scutterbar,435;  holder 

for  screw  tools,  631. 

—  iron  for,  531,  536,  983. 


1471 


INDEX. VOLS.    I.    TO    III. 


Turning  tools  : — Slide  rest. 

—  instruments  for  grinding  and  set- 

ting for  ornamental  turning, 
1162,  1164. 

—  lubricating,  for  metal,  538,  983. 

—  metals,  for,  copper,  gold,  lead,  tin, 

zinc,  &c.  537. 

-  mouldings,  519,  530,  1176. 

—  Nasmy  th's  gage,  for,  534 

—  ornamental  turning,  1162 — 1169. 

—  Roberta's    arrangement    of   slide 

for,  633. 

—  screw  threads  for,  angular,  628 ; 

rounded,  629;  square,  630;  in- 
ternal of  coarse  pitches,  631  ; 
adjusting  penetration  of  tools, 
633. 

—  Shanks'  application  of  two  tools, 

633. 

—  Willis's,  Rev.   Prof.,  cutter  bar, 

997  ;  holder  for  slide  rest,  999  ; 
paper  on  the  principles  of  tools 
for  turning  and  planing  metals, 
991. 

-  wood,  for,  529,  989. 
Turning  vases  from  egg  shells,  155. 

—       works   on,   published  in  England, 

France,  and  Germany,  4 — 8. 
Type  founding,  323. 
—    metal,     composition    of,    277,   293 ; 

mixing,  310. 
Tyrie,  Mr.,  collection  of  Cuban  wood,  81. 


U. 


UNITED  SERVICE  museum  of  woods,  69. 


V. 


VANHAM,  Mr.,  arrangements  of  press,  &c., 
for  working  tortoiseshell,  131. 

Varley,  Mr.  C.,  grinding  lathe  for  lenses  and 
specula,  1269  ;  screw  cutting  apparatus, 
620  ;  working  iron  and  steel,  234. 

Varnishes,  general  remarks  on,  1374. 
amber,  1387. 

—  anime,  1386,  1387- 

—  artists'  virgin  copal,  1385. 

—  black  spirit,  or  lacker,  1398. 

—  body,  1386. 

—  brown  hard  spirit,  1392. 

—  cabinet,  1386. 

—  carriage,  1386. 

—  copal,  1385— 1387. 

—  copal,    spirituous    solutions    of, 

1375,  1394. 

—  crystal,  1 397. 

—  damar,  1376,  1397. 

—  driers  for  body,  1386. 

—  French  polish,  1392. 

—  hard  wood  lacker,  1392. 

—  Indian,  1417. 


Varnishes,  lac,  1392  ;  bleaching,  1393. 

—  lacker,  black,  1398;  brass,  1 395 ; 

hard  wood,  1392. 

—  linseed  oil,  qualities  of,  boiling 

and  clarifying,  1877. 
mastic,  1396. 

—  naphtha,  qualities  of,  1 380. 

—  oil,  preparation  of,  1380  ;  appa- 

ratus used  in,  1381  ;  general 
instructions  for,  1382  ;  usual 
proportions  of  materials,  1388. 

—  paper,  1398. 

—  resins  commonly  used  in  making, 

general  qualities  of,  compared, 
1374—1376. 

—  sealing-wax,  1398. 

—  shell  lac,  1392. 

—  spirit  of  wine,  qualities  of,  tests 

for  strength,  1378  ;  methods 
of  concentrating,  1379. 

—  spirit,   general    instructions   for 

the  preparation  of,  1388 — 
1396. 

—  turpentine,   1397  ;    general    re- 

marks on,  1 388. 
turpentine,  oil  of,  1378. 
wainscot,  1387. 

—  water,  1398. 

—  white  hard,  1391. 

—  white  spirit,  1392.' 

—  wood  oil  used  in  India,  1417. 
Varnishing,   application   of   the  varnishes, 

1399. 

—  atmosphere,       dryness       and 

warmth  essential,  1400. 

—  brushes  for,  1399. 

—  Burmese  ware,  1417. 

—  chilling,  causes  and  correction 

of,  1400. 

—  dry  atmosphere  essential,  1400. 

—  flat  surfaces,  1401. 

—  French  polishing,  1415  ;  rub- 

bers for,  1090,  1414. 

—  hard  wood  turned  works,  1413. 

—  japanning  plain  and  ornamental 

works,  1404  ;  preparation 
of  wood  for,  1405. 

—  lackering  metal  works,  1406  ; 

bronzed,  1413;  circular, 
1409  ;  flat,  1408  ;  heating, 
1407  ;  management  of  the 
brush,  1409. 

—  lackering    hard  wood    turned 

works,  1413. 

—  large  surfaces,  1 402. 

—  painted  works,  1403. 

—  polishing      varnished     works, 

1084,  1101. 

—  sizing,  1403. 
Vases  made  of  egg  shells,  155. 
Vegetable  kingdom,  materials  from  the,  13. 
Veneer   saws,    rectilinear,    725  ;    circular, 

807—814. 


INDEX. VOL8.    I.    TO    III. 


1472 


Veneers,   clamping  while   they   are    being 
worked,  733. 

—  glueing  down,  61. 

—  sawing  by  hand,  805;  large,  with 

segment  saws,  813;  small,  with 

single  plate  saws,  807  ;  spiral, 

154. 
splitting,  large,  Brunei's  machine 

for,  806  ;  small,  805. 
thicknesses  of,  813. 

—  toothing,  61. 
Veneering  curvilinear  works,  62. 

—  flat  works,  61  j  with  the  ham- 

mer, 63. 
Pliny  on,  64. 

—  tortoiseshell  boxes,  134. 
Vice-benches,  855. 

—  clamps,    copper,    iron,  jointed,   lead, 

sloping,  spring,  and  wooden,  859. 

—  flatting,  for  holding  thin  works,  864. 

—  glaziers',    for    drawing   window-lead, 

428. 

—  hand,  861. 

-  Nasmyth  and  Co.'s,  for  cutting  wide 

boiler-plates,  923. 

—  pin,  862. 

-  parallel,  857. 

—  saw,  for  sharpening,  688. 

—  screws,    casting    and    forging,    679  ; 

ball  and  socket  joints  for,  855. 

—  spherical  washer  for,  857. 

—  table,  856. 

—  taper,  for  large  works,  852. 

—  tripod  stand  for,  856. 

—  tail,  855. 

Tine-wood.  See  APRICOT-TREE,  72. 
finhatico.  See  CANARY-WOOD,  78. 
Violet-wood.  See  KING-WOOD,  89. 


W. 


WAINSCOT  OAK,  95  ;  setting  out  for  sawing, 

706. 

varnish,  1387. 
Walrus  teeth,  1 39. 
Walsh,  Mr.,  method  of  originating  screws, 

581;  left  hand,  605. 

Warren,  Mr.,  annealing  steel  plates  for  en- 
graving, 255. 
Warren's  patent  process  for  casting  joiners' 

screws,  679. 

Washing  emery  powder  in  large  and  small 
quantities,  for  grinding  and  pol- 
ishing mechanical  works,  optical 
and  plate  glass,  etc.,  1055. 
—       polishing  powders,  1101. 
iVatch,  compensation  balance  for,  soldering, 

452. 
•    jewelling,   173,  178;  preparation  of 

diamond  powder  for,  1052. 
—     polishing,  brass  work,  1040;  screw- 
heads,  1185;  steel  work,  1075. 


Watch  springs,     manufacture,    value    and 
weight  of,  250. 

Water  of  Ayr  stone  for  polishing,  1065. 

Water  varnishes,  1398. 

Weigall,  Mr.  H.,  ^application  of  the  name 
"onyx,"  1366;  comparative  abilities  of 
English  and  Foreign  gem  engi-avers, 
1362;  gem  and  seal  engraving,  1349. 

Welding  iron.     See  FORGING. 

Welsh,  clearing  stone  for  curriers'  use,  1066; 
oilstone,  1065. 

Whalebone,  preparation  and  uses  of,  135; 
polishing,  1102. 

Wheels,  brush,  for  polishing,  1122. 
buff,  for  polishing,  1118. 

—  change,    for    screw    cutting,    621; 

modes  of  computing  trains,  626. 

—  clock,  formed  by  filing,  981. 

—  cloth,  for  polishing,  1121. 

—  composition,  for  grinding  and  polish- 

ing,  1112. 

—  corundum,  for  grinding  and  polish- 

ing, 1049,  1112. 

—  crocus,  for  sharpening,  1113. 

—  emery,  for  grinding  and  polishing, 

1057,  1113,  1120. 

—  gem  engravers',  1348. 

—  glass  cutters',  1297. 

—  glass  engravers',  1348,  1371. 

—  glaze,  or  wood,  for  polishing,  1117. 

—  grinding  and  polishing,  general  ap- 

plications, and  mechanical  ar- 
rangements, 1102—1122. 

—  key-ways   in,   cutting   with   chisels 

and  files,  885;  engine  for,  900; 
cutters  for,  with  many  points, 
990. 

—  lapidaries',  1034,  1045,  1091.  1113, 

1117,1121,1302,1305. 
laps,    for    grinding    and  polishing, 

1113—1117. 
leather,  for  polishing,  1118—1121. 

—  list,  for  polishing,  1121. 

—  metallic,  or  laps,  for  grinding  and 

polishing,  1113—1117. 

—  seal  engravers',  1348. 
snail,  formed  by  filing,  891. 

—  tires  of  locomotive  engines,  Bodmer's 

method  of  forging,  1021. 

—  wood,    for    polishing     1045,    1115, 

1117. 

—  worm,  668;  cutters  for,  592;  Rams- 

den's  method  of  ratching,  for  cir- 
cular dividing:  engine,  639. 
Whetstones.     See  HONE  SLATES,  1065. 
White,  Mr.,  perpetual  file  with   moveable 

plates,  839. 

White  hard  varnish,  1392. 
Whitehouse,   Mr.   C.,     patent   for   forging 

wrought-iron  tubes,  966. 
Whitelaw,    Mr.  J.,    machine  for  grinding 

cylindrical  rims  of  pulleys,  1242;  rounded 

rims,  1244. 


1473 


INDEX. VOLS.    I.    TO    III. 


White  walnut  wood  (Julians  alba).  See 
HICKORY,  86. 

Whiting,  for  polishing,  1047. 

Whitworth,  Mr.,  on  the  impolicy  of  finishing 
flat  metallic  surfaces  by  grinding,  872; 
system  of  uniform  screw  threads,  670. 

Whitworths,  Messrs.,  key-way  cutter  with 
many  points,  990;  patent  screw  stocks, 
605,  609. 

Wickersley  grindstones,  1064. 

Wilkinson,  Mr.  H.,  ancient  Egyptian  mo- 
saics in  glass,  767;  Damascus  gun  bar- 
rels, 224;  gage  for  fowling  pieces  and 
rifles,  1017. 

Wilkinson's  scissors,  908. 

Willis,  Rev.  Prof.,  blocking  out  gothic  and 
other  mouldings  with  the  circular  saw, 
798;  parallel  guide  for  circular  saw  table, 
759;  vertical  saw  machine  for  curvilinear 
works,  749;  paper  on  the  principles  of 
tools  for  planing  and  turning  metal,  992; 
slide  rest  tools  and  holder,  997;  tool 
holder  for  slide  rests,  999. 

Willow  wood  (Salix),  109. 

Winding  sticks,  application  of,  in  planing 
wood,  500. 

Wine  cooper's  rimer,  573. 

Wire,  binding,  employed  in  soldering,  433. 

—  cutting-nippers  for,  905. 

—  draw-bench  for,  424. 

—  drawing,    423;    lubricating    matters 

used  in,  424,  974. 
-   draw-plates,  with  ruby  holes,  174. 

—  gages  for,  1113,  1114. 

—  joint,  429. 

—  multiform,  for  printing  calico,  427. 

—  oval,  426. 

—  pinion,  426. 

—  straightening,  424. 
Wood  cutter's  saw,  726. 

Wood,  Lieut.  J.  W.,  ice  saw  machine,  741. 
Wood  oil,  used  in  India  as  varnish,  1417. 
Woods  :— 

—  Absorption  of  preservative  fluids  by, 

114,459. 

—  Acacia  (Acacia),  71. 

—  African  black  wood,  71,  74. 

—  African,  mahogany  (Swietenia),  92;  oak, 

96. 

—  Alder  (A  Inus  glutinosa),  7 1 . 

—  Aloes.     See  CALEMBEG,  78. 

—  Almond  tree   (Amygdalus  communis), 

72. 

—  Amboyna.      See  KIABOOCA  WOOD,  38, 

68. 

—  American  maple  (Acer),  93. 

—  Angica.     See  CANGICA  WOOD,  78. 

—  Annual  growth  of,  15,  19. 

—  Apple  tree  (Pyrus  malm),  72. 

—  Apricot  tree  (Armeniaca  vulgaris),  72. 

—  Arbor-vitse  (Thuja),  72. 

—  Arranging  and  collecting  specimens  of, 

67. 


Woods  :— 

—  Ash  tree  (Fraxinus),  73. 

—  Bamboos,  98. 

—  Bar- wood,  73. 

—  Barberry  (Berberis  vulgaris),  73. 

—  Bay  tree  (Laurus  nobilis),  73. 

—  Beech,  (Fagiw  sylvatica),  73. 

—  Beef-wood.     See  BOTANY  BAY  OAK,  75. 

—  Bending  timber,  32. 

—  Betel-nut  palm  (Areca  catechu),  97. 
T-  Birch  (Betula),  74. 

—  Bitter-nut  (Juylans),  74. 

—  Black  Botany  Bay,  74  ;   wastefulness 

of,  24. 

—  Black- wood  tree  (Dalbergia  latifolia 

83. 

—  Blue  gum  wood  (Eucalyptus  piperita) 

86. 

—  Boards,  curvature  of,  51. 

—  Bog  oak,  colour  of,  44. 

—  BOTANICAL  NAMES  OF  : — 

Acacia  (Acacia),  71. 

Acer  (Maple),  93. 

Acer     pseudo-platanus    (Sycamore) 

107. 
^Esculus  Hippocastanum  (Horse  chest 

nut),  87. 

Alnus  glutinosa  (Alder),  71. 
Amygdalus  communis  (Almond  tree) 

72. 

Aquilaria  Agallocha  (Calembeg),  78. 
Araucaria   excelsa    (Norfolk  hlanc 

pine),  37. 
Areca  catechu  (Betel-nut palm),  111 
Armeniaca  vulgaris    (Apricot  tree) 

72. 
Artocarpus  integrifolia  (Jak   wood) 

88. 

Baphia  nitida  (Cam  wood),  78. 
Bauhinise  (Mountain  ebony),  84. 
Berberis  vulgaris  (Barberry  wood),  73 
Betula  (Birch-wood),  74. 
Bignonia  leucoxylon    (  White  cedar) 

80. 
Borassus      flabelliformis     (Palmyra 

wood),  98. 

Buxus  (Box  wood),  76. 
Csesalpinia  echinata   (Brazil  wood) 

77. 

Csesalpini  Sapan  (Sapan  wood),  1 05. 
Calophyllum  (Poon  wood),  102. 
Carpinus  betula  (Hornbeam),  87. 
Casuarina  (Botany  Bay  oak),  75. 
Cedrela  (Cedar),  79. 
Cedrus  (Cedar),  79. 
Celtis  australis  (Nettle  tree),  95. 
Chloroxylon  (Zante),  110. 
Chloroxylon  Swietenia  (Satin  wood), 

105. 

Cissampelos  Pareira,  16. 
Citrus  (Orange  tree),  97. 
Cocos  guianensis  (Prickly-pole  palm). 


INDEX. VOLS.  I.    TO    III. 


1474 


Woods, 

Botanical  names  of: — 

Cocos  nucifera  (Cocoa-nut  palm))  17, 
97. 

Coffea  arabica  (Coffee  tree),  81. 

Cornus  (Dog-wood),  83. 

Corylus  avellana  (Hazel),  86. 

Cratsegus  oxyacantha  (Hawthorn),86. 

Cupressus  (Cypress-tree),  83. 

Cupressus  thyoides  (  White  cedar),  SO. 

Castanea  vesca  (Chesnut),  80. 

Cuticaem,  branco  and  vermo,  41. 

Cydonia  vulgaris  (Quince-tree),  103. 

Cytisus  laburnum  (Laburnum),  89. 

Dalbergia  latifolia  (BlacJcwood-tree), 
83 

Dalbergia  sissoo  (Sissoo-wood),  106. 

Diospyros  (Ebony),  84. 

Diospyros  hirsuta  (Coromandel),  82. 

Erythrina  corallodendron  (Coral- 
wood),  82. 

Eucalyptus  piperita  (Blue  gum-wood), 
86. 

Euonymus  europea  (Spindle-tree),  107. 

Fagus  sylvatica  (Beech-wood),  73. 

Flindersia  australis   (Red  cedar),  80. 

Fourcroya  gigantea  (Pita-wood)t  29. 

Fraxinus  (Ash),  73. 

Gleditschia  triacanthus  (Honey 
locust),  91. 

Guaiacum  (Lignum  vitce)  90. 

Guatteria  virgata  (Lance-wood),  89. 

Guazuma  ulmifolia  (Bastard  cedar,) 
80. 

Gymnocladus  canadensis  (Kentucky 
coffee-tree),  82. 

Haematoxylon  campechianum  (Log- 
wood), 91. 

Heisteria  coccinea  (Partridge-wood), 
99. 

Hippomane  mancinella  (Manchineel) 

Hymenea  courbaril  (Locust-tree),  91. 

Icica  altissima  (Cedar),  80. 

Ilex  (Holly),  86. 

Juglans  alba  (Hickory),  86. 

Juglans  amara,  and  juglans  aquatica 
(Bitter-nut-wood),  74. 

Juglans  regi a  (Walnut-tree),  109. 

Juniperus  (Cedars),  79 — (Juniper- 
wood),  88. 

Knightia  excelsa  (Rewa-rewa),  41. 

Laurus  chloroxylon  (Greenheart),  85. 

Laurus  indica  (Canary-ivood),  78. 

Laurus  nobilis  (Bay-tree),  73. 

Melia  azederach  (  White  cedar),  80. 

Menispermacese,  16. 

Mespilus  germanica  (Medlar-tree),  94. 

Mesua  ferrea  (Iron-wood),  88. 

Metrosideros  vera  (Iron-wood),  88. 

Mimosa  (Rose-wood),  103. 

Mora  excelsa  (Mora-wood),  94. 

Morus  (Mulberry-tree),  94. 

VOL.  III. 


Woods, 

Botanical  names  of  : — 

Morus  tinctoria  (Fustic),  85. 

Nauclea  (  Yellow-wood  ?),  109. 

Olea  europea  (Olive-wood),  96. 

Ostrya  virginica  (Iron-wood),  88. 

Picrsena  excelsa  (Quassia-wood),  103. 

Pinus  (Pines),  100. 

Pinus  Cedrus  (Cedar  of  Lebanon),  79. 

Populus  (Poplar),  102. 

Platanus  (Plane-tree),  101. 

Prunus  (Plum-tree),  102. 

Pterocarpus  santalinus  (J?ed!  sanders) 
103. 

Pyrus  communis  (Pear-tree),  99. 

Pyrus  malus  (Apple-tree),  72. 

Quassia  amara  (Qttcmm),  103. 

Quercus  (0ofc)»  95. 

Rhizophora  (Mangrove),  93. 

Rhuscotinus  (Zante),  110. 

Robinia  pseudacacia  (Locust),  91. 

Robinia  panacoco  (Iron-wood),  88. 

Salix  (Willow),  109. 

Salix  caprea  (Sallow),  104. 

Sambucus  nigra  (Elder-wood),  84. 

Santalum  album  (Sandal-wood),  105. 

Sassafras  officinalis  (Sassafras-wood), 
105. 

Sideroxylon  (Iron-wood),  88. 

Sipiera  (  Greenheart),  86. 

Swietenia  (Mahogany),  91. 

Tapura  guianensis  (Snakewood?),  106. 

Taxus(  Few-free),  110. 

Tectona  grandis  (Teak-wood),  107. 

Thuja  (Arbor  vitce),  72. 

Tilia  europea  (Lime-tree),  90. 

Ulmus  (£?w),  84. 
Woods  :— 

—  Botanical  notes  on,  by  Dr.  Royle,  M.D., 

F.R.S.,  &c.,  71,  110. 

—  Botany  Bay  oak  (Casuarina),  75. 

—  Box  (Buxus),  76. 

—  Branches,  origin  of,  35. 

—  Brazil  (Ccesalpinia  echinata),  77. 

—  Brazilletto  (Ccesalpinia  braziliensis),  77. 

—  Buckum.     See  SAPAN-WOOD,  1 05. 

—  Bullet,  77. 

—  Burrs,  on  teak,  38  ;  yew-tree,  39. 

—  Button  wood  tree.   SeePLANE-TREE,101. 

—  Cabbage.     See  PARTRIDGE-WOOD,  99. 

—  Calembeg  (Aquilaria  Agallocha),  78. 

—  Calamander,   Diospyros   hirsuta.     See 

COROMANDEL,  82. 

—  Calamberri.     See  COROMANDEL,  82. 

—  Caliatour,  40. 

—  Cam  (Baphia  nitida),  78  ;  durability  of 

colour,  45. 

—  Cambium  of,  17. 

—  Campeachy     logwood     (Hcematoxylon 

campechianum).  See  Loo- WOOD,  91. 

—  Camphor  (camphora),  78. 

—  Canary  (Laurus  indica),  78. 

—  Cangica,  78. 


1475 


INDEX. VOL8.    I.    TO    III. 


Woods  :— 

—  Catalogue  of,  commonly  employed  in 

England,  71. 

—  Cedar  (Juniperus,  Cedrela,  &c.),  79. 

—  Cherry-tree  (Cerasus),  80. 

—  Chesnut  (Castanea  vesca),  80. 

—  Clamping,  joints  and  wide  boards,  55. 

—  Cleaver  for  splitting,  25. 

—  Cocoa,  80. 

—  Cocoa-nut  palm  (Cocos  nucifera),  97. 

Sections  of,  17. 

—  Coffee-tree  (Coffea  arabica),  81. 
- —  Collections  of  specimens  of,  68. 

—  Colour,  effects  of,  variation  in,  42. 

—  Coloured  artificially  by  absorption,  115. 

—  Combining  different  pieces  of,  54. 

—  Combustibility  of,  prevented  by  absorp- 

tion, 115,  460. 

—  Compressed,  for  treenails,  29. 

—  Contraction  of,  in  drying,  48,  108. 

—  Coral,  82 

— ,  Coromandel  (Diospyros  hirsuta),  82. 

—  Cowdie    (Dammara     australis).       See 

PINES,  100  ;  expansion  of,  47. 

—  Curls  in,  origin  of,  35. 

—  Cypress  tree  (Cupressus)^  83. 

—  Damask   figures  in,  40. 

—  Darkens  by  exposure  to  light,  or  ac- 

tion of  lime  water,  44. 

—  Deal.     See  PINES,  100. 

—  Decay  of,  22,  113. 

—  Density  of  iron  bark  wood,  29. 

—  Dog  (Oornus),  83. 

—  Door-frames  and  panels,  57. 

—  Dovetail,  clamps,  56  ;  joints,  117. 

—  Drying,  for  japanned  works,  1405. 

—  room  for,  27. 

—  Dry  rot,  22. 

—  Durability  of,  30;  artificially  increased, 

114.     ' 

—  Ebony,  black  (Diospyros),  83. 

—  green,  85. 

—  mountain  (Bauliinice),  84. 

—  Elder  (Sambucus  nigrd),  84. 

—  Elastic  and  non- elastic,  31. 

—  Elm  (Ulmus),  84;  toughness  of,  33. 

—  Endogenous,  17. 

—  Exogenous,  15. 

—  Fibre,  source  of  ornament,  34. 

—  Flexibility  increased  artificially,  115. 

—  Frames  for  panels,  57. 

—  Fustic  (Morus  tinctoria),  85. 

—  Glueing,  works  in,  57. 

—  Granillo,  85. 

—  Green  ebony,  85. 

—  Greenheart  (Laurits  chloroxylori),  85. 

—  Grenadillo,  85. 

—  Growth  of,  14,  19. 

—  Gum  (Eucalyptus),  86. 

—  Gums  and  resins  in,  30. 

—  Hackmetack  larch.     See  PINES,  100. 

—  Hardwoods  used  in  England,  70;  waste- 

fulness of,  20,  24,  28. 


Woods  :— 

—  Hardness  of,  increased  artificially,  115. 

—  Hare.     See  SYCAMORE,  107. 

—  Hawthorn  (Cratcegns  oxyacantha),  86. 

—  Hazle  (Corylus  avellana),  86. 

—  Hickory  (Juglans  alba),  86. 

—  Holly  (Ilex),  86. 

—  Honduras  mahogany  (Swietenia),  92. 

—  Honey  locust  (Gleditchia  triacanthus), 

91. 

—  Hornbeam  (Carpinus  betula),  89. 

—  Horse    chesnut    (dBsculus    hippocasta- 

num),  87. 

—  Horseflesh.     See  MANGROVE,  93. 

—  Indian  blackwood  (Dalbergia  latifolid), 

See  EAST  INDIAN  BLACK-WOOD,  83. 

—  Inflammability  of,  prevented  by  absorp- 

tion, 115,  460. 

—  Ironwood  (Mesuaferrea,etc.'),  87. 

—  Irregular  sections  of,  20. 

—  Jacaranda.     See  ROSE- WOOD,  103. 

—  Jak  (Artocarpus  integrifolia),  88. 

—  Juniper  (Juniperus),  88. 

—  Kiabouca,  88 ;  probably  a  burr,  38. 

—  King,  89. 

—  Knots,  cause  of  ornament  in,  36. 

—  Kaurie     (Dammara     australis).      See 

PINES,  100. 

—  Lace.     See  PLANE-TREE,  101. 

—  Lance  (Gfuatteria  virgata),  89. 

—  Larch.     See  PINES,  100. 

—  Lemon-tree.     See  ORANGE-TREE,  97. 

—  Letter.     See  SNAKE-WOOD,  106. 

—  Lightness  of  Cortina- wood,  29. 

—  Lignum  Rhodium,  104. 

—  Lignum  vitse  (Ouaiacum),  90;  peculiar 

structure  of,  33. 

—  Lime-tree  (Tilia  europea),  90. 

—  Linden- tree,  90. 

—  Live  oak  (Quercus  wrens),  96. 

—  Locust  (Robinia  pseudacacia),  91. 

—  ~Logwood(Hcematoxyloncampechianu')ri), 

91. 

—  Mahogany  (Swietenia),  91. 

—  Manchineel  (Hippomanemancinella)$S. 

—  Mangrove  (Rhizophora),  93. 

—  Maple  (Acer),  93  ;  cause  of  bird's  eye 

figure,  38. 

—  Maracaybo,  94. 

—  Marshall's  «  New  wood,"  113. 

—  Medlar  tree  (Mespilus  germanica),  94. 

—  Medullary  plates  and  rays,  in  15,  40. 

—  Memoir   on   preservation   of,    by  Dr. 

Boucherie,  113. 

—  Micocoulier.     See  NETTLE-IRE'S,  95. 

—  Microscopic  view  of,  28. 

—  Moisture  in,  causes  curvature,  52. 

—  Mora  (Mora  excelsa),  94. 

—  Mortise  and  tenon  joints,  56. 

—  Mosatahiba.     See  MUSTAIBA,  94. 

—  Mountain  ebony  (Bauhinice),  84. 

—  Mulberry-tree  (Morus),  94. 

—  Murraya.     See  BOX-WOOD,  76. 


INDEX. VOLS.    I.    TO    III. 


1476 


Woods  :— 

—  Museums,     containing     collections    of 

specimens,  68. 

—  Mustaiba,  94. 

—  Nepere  palm,  98. 

—  Nettle-tree  (Celtis  australis),  95. 
"New  wood,"  Mr.  Marshall's,  113. 

—  Nicaragua,  95. 

—  Oak  (Quercus),  95. 

—  Olive  (Oka  europea),  96. 

-  Omander.     See  COROMANDEL,  82. 

-  Orange  tree  (Citrus),  97. 

—  Ornamental  characters  of,  34,  64. 

—  Palisander,  99. 

—  Palm-trees,    viz.  —  Betel-nut    (Areca 

catechu);  Cocoa-nut  (Cocos  nucifera); 
Niepere  ;  Prickly  pole  (Cocos  guia- 
nensis) ;  Palmyra  (Borassus  flabelli- 
formis),  97. 

-  Panels  and  frames  of,  57. 

—  Paring- knife,  for  preparing  turnery,  25. 

—  Partridge,  99. 

—  Peach.     See  NICARAGUA-WOOD,  95. 

—  Pear  tree  (Pyrus  communis),  99. 

—  Peon.     See  POON-WOOD,  102. 

—  Pendulums  made  of,  47. 

—  Permanence  of  form  of,  47." 

-  Pernambuco.     See  BRAZIL-WOOD,  77. 

—  Peruvian,  IOC. 

—  Pigeon,  1 00. 

-  Pines  (Pinus),  100. 

—  Pita  (fourcroya  gigantea),  29. 

-  Pith,  governs  form  of  tree,  19. 

—  Plain,  proper  for  mosaic  works,  orna- 
mental turning,  and  carving,  43. 

—  Plane  tree  (Platanus),  101. 

—  Pliny  on,  used  by  the  Romans,  64. 

—  Plum-tree  (Prunus),  102. 

—  Polishing,    flat    works,  1125;    turned 

works,  1123. 

-  Pollards,  beauty  of,  37. 

-  Poon  (Calophyllum),  102. 

—  Poplar  (Populus),  1 02. 

—  Preparing,    for    specimens,    44  ;    for 

turning,  25  ;  with  the  bassoolah,  474, 
953  ;  timber,  26. 

—  Preserving,   Dr.   Boucherie's  memoir 

on,     113,     452;      Kyanizing,     22 
Payne's  process,  953. 

—  Prickly  pole  (Cocos  guianensis),  98. 

—  Princes,  102. 

—  Prize,  102. 

-  Purple,  103. 

-  Purple-heart,  106. 

-  Quassia  (Quassia,  amara,  and  Picrcena 

excelsa),  103. 

—  Queen,  103. 

-  Quince-tree  (Cydonia  vulgaris).      See 

APRICOT- TREE,  72. 

-  Red  gum.     See  GUM-WOOD,  86. 

—  Red  sanders  (Pterocarpus  santalinus), 

103. 

—  Rewa-rewa  (Knightia  excelsa),  41. 


Woods  :— 

—  Rock  elm  (Ulmus),  85. 

—  Roots,  ornamental  grain  of,  37. 

—  Rosewood  (Mimosa),  103. 

—  Rosetta,  103. 

—  Red  deal.     See  PINES,  100. 

—  Ruby.     See  RED  SANDERS,  103. 

—  Russian  maple,  94. 

—  Sallow  (Salix  caprea),  104. 

—  Sandal  (Santalum  album),  105. 

—  Sap,  circulation  of,  20  :  thickness  of, 

21. 
-  Sapan  (Ccesalpinia  sapari),  105. 

—  Sassafras  (Sassafras  officinalis),  105. 

—  Satin-wood     (Chloroxylon    swietenia), 

105. 

—  Saul  (Shorea  rolusta),  106. 

—  Sanders.    See  RED  SANDERS,  103. 

—  Sawing.     See  SAWING. 

—  Scented  by  absorption,  115. 

—  Screws,  threads  for,  667. 

—  Seasoning,  23  ;  for  turnery,  49. 

—  Sections  of,  14,  17,  35,  48. 

—  Septa,  or  silver  grain  of,  40. 

—  Serpentine  grain,  cause  of,  39. 

—  Service-tree,  106. 

—  Ship-building,  timber,  22,  69. 

—  Shrinking  and  warping  of,  22,  47 — 54. 

—  Silver  grain,  or  septa,  40. 

—  Sissoo  (Dalbergia  sissoo),  106. 

—  Snake  (Tapura  guianensis?),  107. 

—  Softening,  by  boiling  and  steaming,  26, 

32. 

—  Spanish  chesnut  (Castanea  vesca).    See 

CHESNUT. 

—  Spanish  mahogany  (Swietenia),  91. 

—  Specific  gravity  of,  29. 

—  Specimens,  collecting  and  arranging,67. 

—  Speckled.     See  SNAKE- WOOD,  106. 

—  Spindle-tree  (Euonymus  europea),  107. 

—  Spiral  growth  of,  52. 

—  Splits  radially  in  drying,  48. 

—  Spruce  deal.     See  PINES,  100. 

—  Stacking  to  dry,  27. 

—  Staining  growing  timber,  43. 

—  Steaming  and  boiling  to  soften,  26,  32. 

—  Stones,  found  in,  20. 

—  Sycamore  (Acerpseudo-platanus),  107. 

—  Table  of,  principally  used  in  England, 

70. 

—  Teak  (Tectona  grandisj,  107  ;   burrs 

of,  38. 

—  Tenon  and  mortise  joints,  56. 

—  Timber,  A.  Aiken,  Esq.,  on,  64. 

—      sawing  at  the  pit,  704,  707. 

—  Toon  (Cedrela  toona),  108. 

—  Tugmutton.     See  BOX-WOOD,  76. 

—  Tulip,  108. 

—  Useful  characters  of,  28. 

—  Variations  of  colour  in,  42. 

—  Variegated  best  for  plain  turning,  43. 

—  Vine.     See  APRICOT-TREE,  72. 

—  Vinhatico.     See  CANARY-WOOD,  78. 


1477 


INDEX. VOLS.    I.    TO    III. 


Woods  :— 

-  Violet.     See  KING-WOOD,  89. 

—  Wainscot  oak,  40,    95  ;    Hassenfratz's 

method   of  setting   out   for  sawing, 
706. 

—  Walnut-tree   (Juglans  regiaj,  109. 

—  Warping  and  shrinking  of,  22,  47,  52, 

115. 

—  Wavy  grain,  cause  of,  39. 

-  White  deal.     See  PINES,  100. 

-  White   walnut   (Juglans  alba).       See 

HICKORY,  86. 

—  Willow  (Salix),  109. 

—  Wych  elm  (Ulmus  montcwa),  85. 

—  Yacca,  109. 

—  Yellow  (Naudea?^  109. 

—  Yellow  deal.     See  PINES,  100. 

—  Yew  tree  (Taxus),  110  ;  burrs  of,  37 ; 

sections  of,  35. 

—  Zante  (Rhus  cotinus  and  Chloroxylori), 

110. 

—  Zebra,  110. 

Woollaston,  Dr.,  on  glaziers'  diamonds,  1 76  ; 

preventing  distortions  in  hardening  steel, 

256  ;  trochometer,  562;  working  platina, 

280. 
Wright,  Mr.  G.,  inventor  of  the  modern 

system  of  boring  large  cylinders,  1010. 


Wright's  machine  for  cutting  joiners'  screws, 

608. 
Wrought  iron.     See  IRON,  WROUGHT. 


Y. 


YACCA-WOOD,  109. 

Yates's  patent  cupola  for  melting  iron,  367. 
Yellow-belly  tortoise-shell,  127. 
Yellow-wood  (Nauclea?),  109. 
Yew-tree  (Taxtis),  110  ;  burrs  of,  37  ;  sec- 
tions of,  35. 
Yorkshire  gritstone,  1064. 


Z. 


ZANTE-WOOD  (Rhus  cotiiws  and   Ckloroxy- 

lon),  110. 
Zebra- wood,  110. 

Zinc,  general  characters,  uses,  and  alloys  of, 
285. 

—  cohesive  force  of,  288  ;  of  alloys,  288. 

—  malleability  of,  295. 

—  polishing  plates  of,  1126. 

Zincing    iron,    Crawford's     process,    971  ; 

Mallett's,  301  :    More  wood   &  Rogers's. 

972. 
Zircon,  1126. 


THE    END. 


ADVERTISEMENTS. 


HOLTZAPFFEL    &    Co., 


N°-  64, 


ENGINE,  LATHE,  &  TOOL  MANUFACTURERS, 


GENERAL    MACHINISTS, 

.  230artr  0f  dh-tmance,  tfje  3&an.  «£a£t  fortrta 


TURNING,  PLANING,  SCREW  AND  WHEEL  CUTTING,  FRAMING,  &c. 
IN  METAL  AND  WOOD  TO  DRAWINGS  OB  MODELS. 


Amateurs 


ARE   SUPPLIED    WITH    THE   APPARATUS,  TOOLS,  AND   MATERIALS,  THAT   ARE   REQUIRED 

IN    TURNING    AND    THE    MECHANICAL    ARTS    GENERALLY,  AND    ARE 

ALSO   PRACTICALLY    INSTRUCTED    IN   THEIR   USE. 


ARCHITECTS. 

COPPERSMITHS. 

MASONS. 

SEAL  ENGRAVERS. 

BOOKBINDERS. 

ENGINEERS. 

MILLWRIGHTS. 

SILVERSMITHS. 

BRUSHMAKERS. 

ENGRAVERS. 

MODELLERS. 

SMITHS. 

BUILDERS. 

GARDENERS. 

OPTICIANS. 

SURVEYORS. 

CABINETMAKERS. 

GUNMAKERS. 

PAINTERS. 

TINSMITHS. 

CARPENTERS. 

HARNESSMAKERS. 

PLASTERERS. 

TURNERS. 

CARVERS.  ; 

HATTERS. 

PLUMBERS. 

WATCHMAKERS. 

CLOCKMAKERS. 

JEWELLERS. 

PRINTERS. 

WHEELWRIGHTS. 

COACHMAKERS. 

MACHINISTS. 

SADDLERS. 

WIREDRA  AVERS. 

AN     EXTENSIVE    ASSORTMENT    OF 

TOOL  CHESTS,  DRESSING-CASES,  DRAWING  AND  MEASURING  INSTRUMENTS, 
PRINTING  PRESSES,  GARDEN  TOOLS,  &c. 


MANUFACTORY,   127,    LONG  ACRE. 


FOREIGN    ORDERS,   RECEIVED   EITHER   DIRECT   OR   THROUGH    AGENCY   HOUSES,   EXECUTED 
WITH    EXACTNESS    AND    DISPATCH. 


STEREOTYPE  IMPRESSION.     PRICE  SIXPENCE. 

1849. 


ADVERTISEMENTS. 


Each  Specimen  on  the  other  side  is  the  result  of  a  different  Apparatus. 

This  page  shows  the  effect  of  the  same  Apparatus,  when  employed  in  conjunc- 
tion with  the  Rose  Engine. 

Although  only  one  Specimen  of  each  individual  Apparatus  is  given,  yet  the 
Patterns,  which  may  be  considered  almost  endless,  depend  on  the  skill  and  taste 
of  the  Operator. 


HCH.TZAPFFKI.  &  Co.'s  C<,n:pnund  Oca/  and  Eccentric  Chuck  with  th"  Rose  Engine. 


ADVEETISEMENTS. 


Oval  Ck*ck. 


Rose 
Engine. 


IBBETSON'S  Geometric  Chuck.— Parts  First,  Second,  and  Third. 


Two  Eccentric 
Movements. 


&  Co.'s  Compound  Oval  and  Eccentric  Chuck. 


ADVERTISEMENTS. 


ADDRESS. 


IT  is  a  source  of  extreme  gratification  to  H.  &  Co.,  to  notice  dib 
extent  to  which  the  Mechanical  Arts,  and  more  particularly  that  of  Turn- 
ing, are  pursued ;  the  Turning  Lathe,  in  its  various  modifications,  assisted 
by  its  appendages  of  mechanism,  being  at  present  absolutely  essential  to 
some  stage  of  every  manufacture. 

The  cultivation  of  Mechanics  by  Gentlemen  who  have  the  advantages 
of  general  acquirements  and  of  leisure,  has  given  rise  to  many  ideas  and 
suggestions  on  their  part,  which  have  led  to  valuable  practical  improve- 
ments. H.  &  Co.  have  a  large  share  of  these  obligations  to  acknow- 
ledge, but  it  would  obviously  be  extremely  difficult  to  particularise  them, 
as  the  ultimate  form  of  any  successful  piece  of  mechanism  is  commonly 
the  result  of  many  successive  modifications. 

In  some  cases  H.  &  Co.  have  been  furnished  by  Gentlemen  with  the 
theoretical  and  general  sketch  of  machines,  the  details  of  construction 
being  entrusted  partially,  or  wholly,  to  themselves ;  and  in  others  they  have 
merely  carried  into  practical  effect  the  finished  designs. 

To  each  of  the  Gentlemen  by  whom  they  have  been  favoured  with 
communications,  as  well  as  to  those  wtee  names  appear  in  this  Catalogue, 
they  beg  to  return  their  most  sincere  thanks,  with  the  assurance  that  it 
\vould  give  them  great  pleasure  to  make  further  additions  to  this  list  under 
similar  circumstances. 

The  public  is  respectfully  invited  to  inspect  H.  &  Co/s  ware-rooms, 
where  may  be  seen  the  principal  part  of  the  tools  and  machines  specified 
in  this  list;  but  of  these  numerous  apparatus,  some  few  are  only  made  to 
order,  and  others  cannot  be  always  in  readiness ;  consequently,  drawings 
of  nearly  the  whole  are  in  preparation,  to  supply  this  inevitable  deficiency. 
The  drawings  are  often  found  to  assist  foreign  Gentlemen,  and  others,  who 
experience  inconvenience  from  being  unacquainted  with  the  technical 
names  of  the  various  apparatus. 

Amateurs  wno  desire  to  receive  instruction  in  Turning  or  Mechanical 
Manipulation  generally,  can  receive  lessons  from  H.  &  Co.'s  experienced 
workmen,  either  in  rooms  fitted  up  for  the  purpose  at  Charing  Cross,  or 
at  their  private  residences,  in  town  or  country. 

No.  64,  CHAUING  CROSS, 
October,  1844. 


ADVERTISEMENTS. 


WORKS    PUBLISHED    BY    HOLTZAPFFEL    &   Co. 

64,  Charing  Cross,  and  127,  Long  Acre,  London. 


A   NEW    SYSTEM    OF    SCALES    OF   EQUAL   PARTS; 

Applicable  to  various  purposes  of  ENGINEERING,  ARCHITKCTURAL,  and  GENERAL 
SCIENCE.  By  CHARLES  HOLTZAPFFEL.  Illustrated  by  a  fac-simile  of  the  scales 
on  copper-plate.  8vo.  cloth,  Price  2s.  6d. 

"  Mr.  HOLTZAPFFEL  could  not  have  done  a  better  service  for  the  profession  than  turning  hit 
attention  to  the  construction  of  scales  suitable  for  their  purposes. —  We  have  for  many  years  been 
in  the  habit  of  using  scales  made  of  paper,  both  for  estimating  and  drawing,  on  account  of  their 
convenience. —  We  have  very  carefully  examined  several  of  the  scales,  and  have  much  pleasure  in 
testifying  their  accuracy  and  utility." — The  Civil  Engineer,  and  Architects'  Journal. 

DESCRIPTIVE   CATALOGUE   OF   THE   WOODS 

COMMONLY  EMPLOYED  IN  THIS  COUNTRY,  FOR  THE  MECHANICAL 
AND  ORNAMENTAL  ARTS. 

INTERSPERSED  WITH  EXTENSIVE  BOTANICAL  NOTES  BY  DR.  ROYLE,  F.R.S.,  L.S., 

AND    G.S.,    ETC.,    ETC. 

The  Descriptive  Catalogue  of  the  Woods,  commonly  employed  in  this  country,  is 
extracted  from  Vol.  I.  of  "  Turning  and  Mechanical  Manipulation"  by  Charles 
Holtzapffel.  The  Catalogue  is  interleaved  and  bound  in  cloth,  for  the  use  of 
Collectors,  Naturalists,  and  Travellers.  8vo.  cloth,  Price  2s.  6d. 

A  NEW  SYSTEM  or  DECIMAL  GAGES  on  MEASURES 

FOR  SHEET  METALS,  WIRES,  AND  SMALL   MANUFACTURED  ARTICLES   GENERALLY. 

Including  the  exact  decimal  values  of  the  gages  now  principally  used  for  these 
purposes  in  the  Mechanical  Arts. 

This  paper  is  extracted  from  the  Appendix  to  Vol.  II.  of  "  Turning  and  Mechanical 
Manipulation,"  by  Charles  Holtzapffel.  Pamphlet  8vo,  in  wrapper,  price  Is. 

PRINTING  APPARATUS  FOR  THE  USE  OF  AMATEURS. 

Containing  full  and  practical  instructions  for  the  use  of  COWPER'S  PARLOUR 
PRINTING  PRESS,  also  the  description  of  larger  presses  on  the  same  principle,  and 
various  other  apparatus  for  the  Amateur  Typographer. 

The  pamphlet  contains  likewise,  numerous  specimens  of  plain  and  ornamental 
types,  brass  rules,  checks,  borders,  ornaments,  corners,  arms,  &c.  &c.  Third 
Edition,  greatly  enlarged.  8vo,  cloth,  Price  2s.  6d. 

HOLTZAPFFEL  AND  CO/S  GENERAL  CATALOGUE 

OF    LATHES,    TOOLS,    AND    INSTRUMENTS    KMPLOYED   IN   THE    MECHANICAL    ARTS 

GENERALLY. 
Stereotype  Edition.     1849.     8vo.  pp.  72,  Price  6d.,  or  free  by  Post,  Is.  4d. 


BRIEF   ACCOUNT    OF   IBBETSON'S    GEOMETRIC 
CHUCK. 

H.  &  Co.  beg  to  announce  that  they  have  purchased  the  remaining  copies  of  the 
pamphlet  written  by  the  late  J.  H.  Ibbetson,  Esq.,  entitled  "  A  brief  Account  of 
Ibbetson's  Geometric  Chuck,  manufactured  by  Holtzapffel  &  Co.,  with  a  Selection 
of  Specimens  illustrative  of  some  of  its  Powers."— Pamphlet  8vo.,  in  coloured 
wrapper,  Price  5s. 


ADVEKTISEMENTS. 


ELLIPTICAL  CUTTING   FRAME. 


MANUFACTURED  BY 

HOLTZAPFFEL  &  CO., 

64,  CHARING  CROSS,  AND  127,  LONG  ACRE,  LONDON. 


THE  ELLIPTICAL  CUTTING  FRAME,  invented  by  CAPTAIN  ASH,  H.E.I.C.S.,  is  employed 
in  the  lathe,  for  ornamenting  turned  surfaces  with  elliptical  figures,  after  the 
same  general  method  that  the  eccentric  cutting  frame  is  employed  for  producing 
circular  figures  on  similar  surfaces ;  viz.,  the  object  to  be  ornamented  is  fixed  on 
the  lathe  mandrel,  and  motion  is  given  to  the  tool  by  the  Elliptical  Cutting  Frame, 
which  is  fitted  to  the  receptacle  of  the  sliding  rest,  and  driven  by  a  band  leading 
from  the  overhead  motion. 

The  Elliptical  Cutting  Frame  is  capable  of  producing  ellipses  of  all  proportions, 
from  a  right  line  to  a  circle,  according  as  it  may  be  adjusted  ;  and  the  ellipses  may 
be  arranged  either  in  circular  order  by  the  employment  of  the  division  plate,  or  in 
rectilinear  order  by  the  motion  of  the  sliding  rest ;  or  the  two  movements  may  be 
combined  at  pleasure.  An  almost  infinite  variety  of  patterns  of  a  highly  ornamental 


Pattern  1. 


Pattern  2. 


ADVERTISEMENTS. 


ELLIPTICAL  CUTTING   FRAME. 

character  will,  therefore,  be  produced  by  the  elliptical  movement  alone.  In  addition 
to  which,  the  instrument  is  adapted  to  produce  epicycloidal  patterns  of  4  loops, 
similar  to  those  produced  in  the  geometric  chuck  ;  these  looped  figures  may 
likewise  be  made  in  all  proportions,  and  be  placed  in  any  positions. 


Pattern  3. 


Pattern  4. 


From  these  comprehensive  powers  of  the  Elliptical  Cutting  Frame,  it  results  that 
any  desired  arrangements  may  be  produced  of  circles,  ellipses,  right  lines,  or 
4-looped  figures  :  the  instrument  is,  therefore,  a  most  desirable  addition  to  all  lathes 
for  ornamental  turning,  and,  if  required,  its  powers  may  be  still  further  increased 
by  the  addition  of  other  epicycloidal  patterns,  or  by  combining  its  movements  with 
those  of  the  eccentric  chuck  or  other  apparatus  for  ornamental  turning. 


General  Remarks  on  the  Action  of  the  ELLIPTICAL  CUTTING  FKAME. 

The  elliptical  movement  of  the  tool  is  produced  as  in  the  geometric  pen,  and  in 
Ibbetson's  geometric  chuck,  by  the  combination  of  two  circular  movements  in  oppo- 
site directions,  the  one  of  which  travels  at  double  the  angular  velocity  of  the  other. 
In  the  Elliptical  Cutting  Frame  this  is  effected  by  the  train  of  wheels  seen  in  the 
front  of  the  instniment,  which  are  so  arranged  that  the  eccentric  frame  carrying 
the  tool  A  makes  two  revolutions  to  the  right,  while  the  radial  flange  B  makes  one 
revolution  to  the  left ;  and  the  proportions  of  the  ellipse  described  by  the  tool  depend 
upon  the  relative  degrees  of  eccentricity  given  to  A  and  B.  Thus,  when  A  and  B 
are  both  placed  central,  the  tool  has  no  eccentricity,  and  merely  produces  a  dot. 
When  eccentricity  is  given  to  A  alone,  the  tool  describes  a  circle,  the  radius  of 
which  will  depend  upon  the  movement  given  to  the  screw  of  the  eccentric  frame, 
under  the  guidance  of  the  micrometer  head  C,  which  has  ten  divisions.  Supposing 
the  eccentricity  to  be  equal  to  4  turns  of  the  screw,  or  40  divisions  of  the  micrometer 
head,  and  that  it  is  desired  to  convert  the  circle  into  a  straight  line,  the  flange  B  is 
also  moved  40  divisions,  by  means  of  the  adjusting  screw  D,  upon  which  a  winch 
handle  is  temporarily  fitted. 

Any  series  of  ellipses  between  the  straight  line  and  the  circle  may  be  described 
by  reducing  the  eccentricity  of  the  radial  flange  B.  Thus,  if  it  be  shifted  5  divisions 
between  each  figure,  a  series  of  7  ellipses  will  be  produced,  gradually  advancing  from 
the  right  line  to  the  circle.  Any  other  number  of  divisions  may  be  adopted  in  the 
same  manner  ;  the  instrument  being  so  adjusted  that  equal  numbers  of  divisions  on 
B  and  C  always  produce  the  straight  line.  Series  of  concentric  ellipses  are  pro- 
duced by  adjusting  both  A  and  B  ;  thus,  in  pattern  1,  A  was  shifted  4  divisions,  and 
B  two  divisions  between  every  cut. 


ADVERTISEMENTS. 


ELLIPTICAL   CUTTING  FRAME. 

The  radial  action  of  the  flange  B,  however,  has  the  effect  of  placing  the  ellipses 
oblique  to  each  other,  instead  of  parallel,  and  this  requires  some  compensation  to  be 
introduced.  CAPTAIN  ASH  compensated  the  obliquity  by  shifting  the  division  plate 
of  the  lathe  a  proportionate  quantity.  Subsequently,  the  spindle  was  extended 
through  the  stem  of  the  instrument,  and  a  graduated  disk  fixed  on  the  end  of  the 
spindle  was  employed  for  the  compensation,  but  which  is  more  conveniently  and 
accurately  effected  by  means  of  the  worm  wheel  and  tangent  screw  movement^ 
suggested  by  H.  PERIGAL,  Esq.,  F.R.A.S.  The  tangent  screw  E  is  moved  by  a 
winch  handle,  and  has  a  micrometer  so  arranged,  that  the  movement  indicated  by 
one  division  exactly  compensates  the  obliquity  produced  by  moving  the  flange  B  one 
division;  and  therefore,  to  ensure  the  parallelism  of  the  ellipses,  it  is  only  necessary 
to  employ  the  same  number  of  divisions  on  B  and  E.  The  tangent  screw  movement 
may  also  be  employed^  to  give  any  angular  position  to  the  ellipses  that  may  be 
required.  Thus,  the  worm  wheel  having  150  teeth,  37^  turns  of  the  tangent  screw 
will  place  any  of  the  figures  at  right  angles  to  their  former  positions. 

The  4-looped  figures  are  produced  by  changing  the  train  of  wheels.  For  the 
ellipses,  the  train  consists  of  a  fixed  wheel  of  48  teeth,  leading  into  one  of  24,  to 
which  is  attached  a  36  wheel,  leading  into  another  36  wheel  fixed  to  the  axis  carry- 
ing the  eccentric  frame  A.  For  4-looped  figures,  the  relative  velocity  of  the 
eccentric  frame  is  doubled  by  employing  wheels  of  48  and  24  teeth,  instead  of  the 
pair  of  36  wheels.  The  adjustment  of  the  4-looped  figures,  for  eccentricity  and 
position,  is  effected  in  the  same  general  manner  as  the  adjustment  of  the  elliptical 
figures. 

In  the  illustrations  shown  on  the  previous  pages,  Pattern  1  consists  of  ellipses 
only ;  the  two  central  series  are  placed  at  right  angles  by  the  division  plate  of  the 
lathe.  The  positions  of  the  outer  series  are  also  determined  by  the  division  plate, 
and  the  ellipses  are  made  to  intersect,  by  moving  the  slide  rest  screw  between  every 
cut.  Pattern  2  is  produced  by  the  right  line  and  4-looped  movements.  The 
positions  of  the  right  lines  are  determined  by  the  division  plate,  and  the  series  of 
ten  4-looped  figures  are  interposed  either  by  the  tangent  screw  E,  or  by  the  division 
plate.  Pattern  3  consists  of  ellipses  and  looped  figures.  The  positions  of  the  ellipses 
constituting  the  central  portion  of  the  pattern,  and  the  small  4-looped  figures  of 
which  the  border  is  composed,  are  given  by  the  division  plate  and  sliding  rest.  The 
general  position  of  the  intermediate  series  of  4-looped  figures  is  also  given  in  the 
same  manner  ;  but  the  figures  being  eccentric,  are  duplicated  by  shifting  the  tangent 
screw  E  18|  turns.  Pattern  4  shows  a  modification  of  the  4-looped  figure  in  which 
the  eccentricities  of  A  and  B  are  in  the  proportion  of  1  to  8.  Thus,  in  producing 
each  of  the  sixteen  squares  of  the  central  figure,  A  was  3,  and  B  24,  divisions  eccen- 
tric, and  the  lines  were  doubled  by  reducing  the  eccentricity  of  A  ^,  and  B  2 
divisions.  The  local  positions  of  the  squares  were  determined  by  the  division  plate, 
but  8  were  worked  with  E  central,  and  for  the  other  8,  E  was  shifted  18f  turns. 
The  border  consists  of  72  squares,  for  which  A  was  one,  and  B  8  divisions  eccentric, 
36  of  the  squares  were  worked  with  E  inclined  9|  divisions  to  tha- right,  and  for  the 
intermediate  36  squares,  E  was  inclined  an  equal  quantity  to  the  left. 


ADVERTISEMENTS. 


HOLTZAPFFEL  &  CO.'S 

PEN-HOLDER  FOR  ENFEEBLED  HANDS. 


THE  Pen-holder  for  enfeebled  hands  was  invented  for  the  use  of  those  persons 
who,  from  age,  rheumatism,  gout,  stiffness  in  the  joints  of  the  fingers,  defects  in 
the  nerves  of  the  hands,  paralysis,  or  other  infirmity,  are  deprived  of  the  free  use  of 
the  fingers,  so  that  they  cannot  hold  a  pen  in  the  customary  position. 

The  instrument  is  represented  in  three  views  :  in  the  center  as  closed  for  the 
pocket ;  on  the  left  as  opened  for  use  ;  and  on  the  right  in  the  act  of  being  used. 
The  shaft  of  the  Pen-holder  for  enfeebled  hands  is  held  quite  vertically  in  the 
central  part  of  the  hand,  and  grasped  by  the  whole  of  the  fingers ;  this  position  the 
most  infirm  can  usually  command.  The  lower  extremity  of  the  shaft  is  allowed  to 
rest  firmly  upon  the  paper,  and  thereby  support  the  hand,  whilst  the  socket  that 
actually  receives  the  pen  or  nib  is  jointed  to  the  vertical  shaft  at  about  the  angle  of 
45  degrees,  and  is  pressed  on  the  paper  by  a  feeble  spring,  so  as  to  assimilate  in  the 
closest  manner  to  the  action  of  the  ordinary  quill  pen.  The  Pen-holder  for  enfeebled 
hands  will  be  used  with  more  freedom  when  neither  the  hand  nor  the  arm  rest 
upon  the  paper,  but  the  little  finger  should  almost  touch  the  sloping  socket. 

The  Pen-holder  is  adapted  to  receive  a  gold,  steel,  or  quill  pen,  at  the  option  of 
the  individual ;  and  the  instrument  may  be  carried  in  the  pocket  as  an  ordinary 
pencil-case.  The  purpose  of  the  screw  at  the  bottom  of  the  holder  is  to  adapt  the 
length  of  the  vertical  shaft  to  the  projection  of  the  pen,  as  when  the  latter  touches 
the  paper,  the  length  of  the  central  shaft  should  be  such  as  just  to  give  the  shaft 
the  vertical  position.  Whereas,  if  the  pen  should  project  too  much,  or  too  little, 
it  will  be  needful  to  incline  the  shaft  to,  or  from,  the  individual,  which  it  is  desirable 
to  avoid. 


Price  of  the  Pen-holder  /or  Enfeebled  Hands,  in 
Gold  Pen,  II.  16s. 


,  with  Everlasting 


ADVERTISEMENTS. 


COWPER'S   PARLOUR    PRINTING  PRESS. 

MADE  ONLY  BY  HOLTZAPFFEL  &  CO., 
64,   CHARING  CROSS,  AND   127,  LONG  ACRE,   LONDON. 


THIS  little  Printing  Press  is  made  of  mahogany,  and  stands  in  the  small  space  of 
1 1  by  8  inches.  It  is  capable  of  printing  a  page  7  by  6  inches,  and  works  so  easily 
that  a  child  may  use  it  on  the  parlour  table.  A  small  type-case  accompanies  it, 
containing  a  fonte  of  about  2500  types,  neatly  arranged  in  three  drawers  with 
appropriate  divisions  ;  a  fourth  drawer  serves  for  the  furniture,  inking  tablet,  &c.  ; 
and  to  these  are  added  the  necessary  tools,  so  as  to  render  the  whole  complete. 
Should  it  be  required,  the  type-case  will  contain  a  duplicate  supply  of  type  in 
addition  to  that  usually  furnished,  and  which  doubles  the  efficiency  of  the  apparatus 
at  a  slight  additional  cost. 

The  above  apparatus  is  well  adapted  to  the  amusement  and  education  of  youth, 
and  also  to  various  applications  of  the  inestimable  typographic  art  to  the  common 
concerns  of  mankind. 

For  example. — Companies,  institutions,  and  individuals,  have  found  it  convenient 
for  circular  letters,  invoices,  and  papers,  subservient  to  the  despatch  and  methodical 
arrangement  of  business  ;  naturalists  and  travellers  for  short  memoirs  of  scientific 
researches,  or  labels  for  specimens  ;  the  friends  of  education,  for  disseminating 
original  and  other  papers ;  wood-engravers,  for  examining  the  progress  of  their 
blocks  :  practical  printers,  for  proofs  of  title-pages,  stereotype  plates,  or  cards ;  and 
nearly  every  different  pursuit  will  suggest  some  new  application  of  this  little  Press. 

LIST  OF  PRICES. 
SECTION  I. — COWPER'S  PARLOUR  PRESSES  AND  APPARATUS. 

COWPER'S    PARLOUR  PRINTING  PRESS,  with  a  galley-chase,  a  box  of  ink,  a    £   s.    d. 
composition  inking  roller,  and  a  distributing  tray 1140 

SMALL  DEAL  TYPE  CASE,  painted,  with  four  drawers  ;  three  of  them  partitioned 
to  contain  an  assortment  of  about  2500  types,  and  a  proportionate  supply  of 
leads  and  brass  rule ;  the  fourth  drawer  contains  reglet,  furniture,  side  and 
foot  sticks,  quoins,  &c. 2  16  0 

SET  OF  EXTRAS— comprising  transfer  composing  stick,  bodkin,  forceps,  mallet, 
shooting-stick,  planer,  brush,  and  turpentine  for  cleaning  the  type,  two  quires 
of  demy  printing  paper,  cut  into  suitable  sizes  for  the  press,  and  one  pair  of 


GALLEY  CHASE  seven  inches  square  inside    .                  

040 

Total  charge  for  the  Plain  Parlour  Prets  and  Apparatus  complete 

560 

COWPER'S  PARLOUR    PRINTING   PRESS,  japanned  and  finished  in  the  best 
manner,  and  fitted  with  a  drawer,  in  other  respects  as  above  .... 
SMALL  MAHOGANY  TYPE  CASE,  with  brass  lock  and  handles,  in  other  respects 

220 

440 

SET  OF  EXTRAS,  comprising  Transfer  Composing-stick,  &c.,  as  above    . 
GALLEY-CHASE  seven  inches  square  inside  
Total  charge  for  the  Best  Parlour  Press  and  Apparatus  complete 

DUPLICATE  SET    OF  2600  TYPES,  and  which  may  be  contained  in  either  of  the 
above  cases  

0  12    C 
040 

~7     2~~0 

1    12    0 

ADVERTISEMENTS. 


990 
0  10  fi 
080 


15    2    0 


SECTION  II. — FOLIO  FOOLSCAP  PRESSES  AND  APFAUATUS. 

FOLIO  FOOLSCAP  PRINTING  PRESS,  on  the  principle  of  Cowper's  Parlour  Press, 
suitable  to  printing  the  half  sheet  of  Foolscap,  or  the  quarto  sheet  of  Imperial! 
External  measurement  of  the  press  21  by  11  inches,  measurement  of  the  bed  15 
by  10  inches,  with  two  iron  chases,  register  points,  &c.  The  press  varnished 
and  japanned,  complete .  .  .  4  H  <J 

LARGE  DEAL  TYPE  CASK,  with  six  drawers,  and  measuring  externally  2  inches 
by  18,  and  11  inches  high,  with  iron  handles,  lock  and  key 

Four  of  the  drawers  are  partitioned  after  the  Printer's  method  for  holding  9000  types  of 
the  following  varieties. 

GRKAT  PRIMER,  ROMAN  Specimen  No.  9  viz.,  capitals,  figures,  points,  spaces, 
quadrats,  &c. 

PICA,  ROWAN,  No.  13;  large  and  small  capitals,  lower  case  (bmall  letters),  with  accented 
vowels  for  printing  the  foreign  languages,  figures,  points,  spaces,  quadrats,  and 
space  line  leads,  complete. 

BOURGEOIS  ROMAN,  No.  17 ;  capitals,  figures,  points,  spaces,  quadrats,  &c. 

BOURGEOIS  ANTJQUS,  No.  23 ;  capitals,  figures,  points,  spaces,  quadrats,  &c. 

Two  of  the  drawers  contain  space  line  leads,  furniture,  side  and  foot  sticks,  quoins,  and 
reglet ;  also  a  mallet,  shooting  stick,  planer,  bodkin,  printer's  composing  stick 
finches  long,  brush  for  cleaning  the  type,  a  pair  of  thick  damping  slates,  &c., 
all  proportioned  to  the  size  of  the  Foolscap  Press 

Six  inch  composition  inking  roller  in  frame  and  case          ...... 

Large  box  of  superfine  printing  ink 

Total  charge  for  the  Folio  Foolscap  Press  and  Apparatus  in  the  less  complete  form 

FOLIO  FOOLSCAP  PRINTING  PRESS,  exactly  like  the  one  last  described,  but 
with  the  following  additions,  namely,  an  iron  bed  half  an  inch  thick,  planed 
quite  level  and  true,  to  increase  the  permanent  accuracy  of  the  Foolscap  Press, 
and  an  iron  counterpoise,  to  facilitate  the  working  of  the  same  .  .  .770 

LARGE  DEAL  TYPE  CASE  with  eight  drawers,  similar  to  the  case  with  six 
drawers  above  described,  but  three  inches  higher,  and  containing  a  considerably 
greater  supply  of  each  of  the  kinds  of  type  specified  in  the  foregoing  descrip- 
tion, together  with  the  addition  of  Great  Primer  No.  9,  lower  case  letters,  Pica 
Italic  No.  14.  capitals,  lower  case  letters,  points,  and  spaces,  and  Bourgeois 
Antique  No.  23.  lower  case  letters,  making  the  total  number  of  types  about 
17,000 ;  together  with  a  proportionate  increase  of  space  line  leads,  furniture, 
&c.,  and  with  the  addition  of  21  pieces  of  brass  rule  of  three  varieties,  and  all 
16  inches  long 16  16  0 

Six  inch  composition  inking  roller  in  frame  and  case 0  10    fi 

Large  box  of  superfine  printing  ink .         .         .080 

Composing  frame  to  receive  the  drawers  of  the  type  case  when  in  use          .         .         .140 

Inclined  galley  with  moveable  bottom .        0  18    0 

Four  <jxtra  chases,  two  of  them  with  crosses 0  10    0 

Total  charge  for  the  Folio  Foolscap  Press  and  Apparatus  in  the  more  complete  form      27  13    6 

SECTION  III— CASES  FOR  ADDITIONAL  TYPES. 
SMALL  TYPE  TRAY,  lo  by  6  inches,  with  a  selection  of  about  COO  Roman  or  Italic 

typesof  small  size,  of  either  of  the  numbers  17  to  20 0  15    0 

The  empty  type  tray 050 

TYPE  BOOK  15  by  12  inches,  with  a  selection  of  about  1500  types,  comprising  8  varie- 
ties of  small  types  for  headings,  cards,  &c.,  as  described  on  page  55  of  pamphlet  220 

The  empty  type  book 0  12    0 

LARGE  TYPE  TRAY  22  by  24  inches,  partitioned  after  the  mode  of  the  printing 
office,  for  containing  larger  quantities  of  type  of  any  kind ;  namely,  the  tray 

without  types 070 

MUSIC  TYPE  CASE  of  deal,  painted,  uniform  in  size  with  the  Small  Deal  Type 
Case  described  on  page  11.  The  Music  Type  Case  contains  four  drawers,  the 
whole  of  which  are  partitioned  to  receive  an  assortment  of  2800  music  types, 
of  200  different  kinds,  as  described  on.  page  49  of  the  pamphlet.  The  case  with 

music  types  complete  .         .         . '5156 

HAND  CHASE,  in  a  painted  case,  with  cushion,  roller,  ink,  and  inking  tray     .         .        0  15    0 
The  Hand  Chase  alone •         •       •        0    7    ti 

PRINTING  APPARATUS  FOR  THE  USE  OF  AMATEURS. 

A  pamphlet  containing  full  and  practical  instructions  for  the  use  of  COWPER'S  PARLOUR 

PRINTING  PRESS,  also  the  description  of  larger  presses  on  the  same  principle,  and  various  other 

apparatus  for  the  Amateur  Typographer. ^-The  pamphlet  contains  likewise,  numerous  specimens 

of  plain  and  ornamental  types,  brass  rules,  checks,  borders,  ornaments,  corners,  arms,  $c.  Ac 

Third  Edition,  greatly  enlarged.    8vo.  cloth,  Price  2s.  6d. 

Specimens  of  the  types  separately.     Price  6d 


ADVERTISEMENTS. 


A  NEW  SYSTEM  OF  SCALES  OF  EQUAL  PARTS, 

Applicable  to  various  purposes  of  ENGINEERING,  ARCHITECTURAL,  and  GENERAL 
SCIENCE.  Illustrated  by  a  fac-simile  of  the  scales  on  copper-plate.  By  CHARLES 
HOLTZAPFFEL.  8vo.  cloth,  Price  2s.  6d.  Published  by  JOHN  WEALE,  London.  Sold 
also  by  HOLTZAPFFEL  &  Co.,  Engine,  Lathe,  and  Tool  Manufacturers,  64,  Charing 
Cross,  and  1'27  Long  Acre,  London. 

"  Mr  HOLTZAPFFEL  could  not  have  done  a  better  service  for  the  profession,  than  turning  his  attention 
to  the  construction  of  scales  suitable  for  their  purposes.—  We  have  for  many  years  been  in  the  habit  <>; 
\uing  scales  made  of  paper,  both  for  estimating  and  drawing,  on  account  of  their  convenience.—  We  hai-t 
u:ry  carefully  examined  several  of  the  scales,  and  have  much  pleasure  in  testifying  their  accuracy  and 
utility."— The  Civil  Engineer  and  Architects'  Journal. 

IIOLTZAPFFEL  AND  CO.'S. 
ENGINE -DIVIDED     SCALES, 

APPLICABLE    TO 

j,  &rcf)ittctut:al,  antJ  Central  Defence. 

As  the  least  expensive  fabric,  each  scale  is  ruled  in  the  Dividing  Engine,  on  a  different 
slip  of  card  paper,  18  inches  long,  the  figures  and  inscription  having  been  previously 
printed  dry.  By  this  arrangement  the  confusion  of  crowded  scales  is  entirely  avoided, 
nnd  any  of  them  may  be  applied  directly  to  the  drawing,  or  compared  with  one  another, 
without  the  employment  of  the  compasses.  The  material  of  the  scales  and  of  the 
drawing  paper  being  IDENTICAL,  they  will  be  found  well  adapted  to  the  majority  of  the 
drawings  used  in  common  practice.  Numerous  experiments  on  this  head  are  detailed 
in  the  pamphlet. 

ORDINARY  DRAWING  SCALES. 

A  series  of  24  scales,  containingthe  usual  reductions  of  the  foot,  from  one  sixteenth  of  an  inch  to  G  inches 
to  the  foot,  including  three  lines  of  inches,  divided  into  eighths,  tenths,  and  twelfths,  and  the  English  foot 
decimally  divided.  Sold  also  in  quarter-sets,  or  singly. 

CHAIN  SCALES. 

A  series  of  12  scales  in  chains  and  links,  namely,  1,  14,  2,  3,  4,  6,  8,  10,  16,  20,  30,  40,  chains  to  the 
inch  •  various  others,  and  also  scales  of  chains  and  miles  expressed  iu  feet. 

PROPORTIONAL  SCALES. 

A  series  of  25  Proportional  Scales,  for  the  enlargement  and  diminution  of  drawings  and  models,  so  as 
M  suit  all  transpositions  of  scale,  required  by  the  limitation  of  the  drawing  paper,  the  copper  plate,  or 
of  the  materials  to  he  used  in  the  Lathe  or  otherwise.  The  series  gives  400  distinct  and  different  ratios 
of  proportion,  which  are  given  in  a  tabular  form  in  the  Pamphlet. 

COMPARATIVE  SCALES. 

A  series  of  24  Comparative  Scales,  by  which  any  length  in  Berlin,  Brussels,  English,  Florence, 
French,  Leipsic,  Lisbon,  Munich,  Neapolitan,  Polish,  Rhineland,  Roman,  Sicilian,  Spanish,  Swedish, 
Venetian,  Vienna,  measures,  whether  in  feet,  bracchi,  palms,  inches,  or  parts,  can  be  transposed  on 
inspection  into  corresponding  quantities,  expressed  in  any  other  of  the  linear  measures  of  the  series. 

The  same  method  is  equally  applicable  to  the  transposition  of  the  measures,  weights,  moneys,  miles, 
leagues,  &c.  of  different  Countries,  and  for  any  of  which  purposes,  scales  will  be  made  to  order,  from  the 
measures  of  the  Ncitional  Standards  given  in  KELLY'S  CAMBIST. 

A  series  of  24  Scales  for  showing  the  comparative  bulks  and  weights  of  equal  quantities  of  the  metals, 
woods,  stones,  and  materials  principally  used  in  the  arts.  Contraction  Rules,  used  in  making  foundry 
patterns. 

Any  of  the  above,  and  many  other  Scales  (fully  described  in  the  Pamphlet), graduated  on  separate  slipt 
of  Card  Board,  18  inches  long,  at  9s.  the  dozen,  or  separately,  at  \s.  each.  If  ruled  to  order,  2s.  each. 
Cases  covered  with  cloth,  for  one  dozen,  Is.  Qd. ;  for  two  dozen,  2s.  each. 


THE  LIBRARY,  SKETCHING  OR  POCKET-BOOK  SCALE. 


CZI 


A  rectangle  of  card,  43  by  2s-,  cut  out  in  the  annexed  form,  and  divided  on  the  several 
edges.  It  combines  the  Protractor,  and  all  the  usual  Scales  for  Drawing,  and  it  may  be 
used  as  a  set  square,  or  bevil,  parallel  rule,  Marquois  Scale,  &c.  Price,  on  card,  3s. ,  4*., 
5*.,  according  to  the  number  of  graduations. 

THE  ODONTOGRAPII, 
Invented  by  the  Rev.  R.  WILLIS,  A.M.,  F.R.S.,  Jacksonian  Professor,  Cambridge,  $e. 

This  is  an  instrument  of  easy  application,  used  for  describing  the  teeth  of  wheels  by  circular  arcs,  so 
that  any  two  wheels  of  a  set  may  »ork  truly  together.  Price  of  the  Odontograph  on  card  and  varnished,  5s. 

The  theoretical  explanation  of  this  system  of  teeth,  which  has  been  extensively  adopted  by  practical  men, 
will  be  found  in  the  Trans.  Inst.  Civil  Tngineers,  Vol.  II.,  and  in  Willis's  Principles  of  Mechanism,  1842. 


ADVERTISEMENTS. 


Entex 

TO 

THE    LEADING    ARTICLES. 


BORING  TOOLS.    (See  also  Drilling  Tools) 

Nos.  1040 

to       1066      Page 

10 

CUTLERY      

..     1151 

.  .      1229 

13 

DRAWING  INSTRUMENTS    

..     1242 

..      1310 

16 

DRILLING  TOOLS      

..    1315 

.  .      1336 

20 

ENGRAVERS'  TOOLS      

..     1342 

.  .      1353 

22 

FILES,  SHEFFIELD  AND  LANCASHIRE 

..     1356 

..      1365 

22 

FORGING  TOOLS   

.  .     1367 

..      1376 

23 

GAGES       

.  .    1380 

.  .      1394 

23 

GEOLOGICAL  TOOLS      

..    1396 

..      1401 

24 

GRINDING  APPARATUS   

..    1425 

..      1436 

25 

LATHES,—  COMPLETE  LATHES      

..    1480 

..      1518 

28 

LATHES,  —  DETACHED  PARTS  OF  ;  namely  :  — 

..    1519 

..      1541 

35 

Chucks  for  Fixing  Works  in  the  Lathe   - 

..     1542 

..      1576 

36 

Chucks  for  Ornamenting  Works  in  the  Lathe 

..    1577 

..      1593 

39 

Slide  Rests,  &c.,  for  Ornamental  Turning 

..    1594 

..      1616 

40 

Slide  Rests,  &c.,  for  Metal  Turning    -    - 

..    1617 

.  .      1628 

42 

Miscellaneous  Lathe  Apparatus  -    -    -    - 

..    1629 

.  .      1643 

43 

PLANES     

..    1687 

..      1714 

45 

PLANING  BENCHES       

..    1715 

..      1719 

46 

PRUNING  AND  GARDENING  TOOLS      - 

..    1730 

.  .      1750 

47 

ROSE  ENGINES      

..    1764 

.  .      1780 

49 

RULES  

..    1782 

..      1793 

50 

SAWS    

..    1794 

..      1818 

51 

SAWING  MACHINES      

..    1819 

.  .      1832 

52 

SCREW  CUTTING  APPARATUS      -    -    - 

..    1841 

..      1856 

53 

SQUARES       

..    1897 

..      1910 

54 

TOOL  CHESTS    

..    1936 

..  .    1978 

56 

TURNING  TOOLS        

..    1986 

.  .      2027 

64 

TURNING  TOOL-CHESTS   

..    2028 

.  .      2036 

65 

VICES   

..    2040 

.  .      2055 

66 

WHEELS        

..    2058 

.  .      2064 

66 

WOODS      -    -    - 

..    2076 

.  .      2078 

67 

TABLE  KNIVES  AND  FORKS,  &c.  -    -    - 

APPENDIX  A. 

68 

COWPER'S  PARLOUR  PRINTING  PRESS, 

&c.      -    - 

B. 

69 

ENGINE-DIVIDED  SCALES    

C. 

70 

ADVERTISEMENTS. 


GENERAL    CATALOGUE 


MANUFACTURED   AND   SOLD   BY 


HOLTZAPFFEL    AND    CO., 

04,  CHARING  CROSS,  AND  127,  LONG  ACRE,  LONDON. 


REVISED  AND  ENLARGED,  1844. 


No.  \£ 

1000  AT^ZES.   Carpenters,  Coopers,  and  Shipwrights  adzes.  -    -  Each  0 

1001  ANVILS.  Small  anvils,  of  the  Ordnance  pattern,  with  shanks  for 

the  bench  or  vice  ;  some  with  2  cutters    -    «•    -    -  Each  0 

1002 Smiths  anvils,  from  20  to  400  Ibs.  weight     -    -    -     The  lb.\Q 

1003  Smiths  anvils,  with  complete  sets  of  Forging  Tools,  or  com- 
plete sets  of  Farriers'  To^ls The  set  6 

1004 Tripod  anvil  stands  of  cast  iron,  with  springs  to  reduce  thel 

concussion  arising  from  the  hammer.  -----  Each^l 

1005   AUGERS.  Shell  augers,  from  |  to  1£  inch,  short  with  tangs 0 

1 006 Shell  augers,  long,  with  eyes 0 

1007  Screw  augers 0 

1008 Improved  American  screw  augers,  from  i  to  2  inch,  with 

worms  soldered  on,  and  shifting  cutters    -     ...  Each  0 

J009  Screw  and  Shell  augers,  in  sets  of  G  to  12,  and  from  §  to 

1^-inch  diameter,  to  fit  handles  of  beech-wood  or  hard- 
wood, with  spring  sockets.       -    - The  sell 

1010  AWLS.  Brad,  flooring,  and  saddlers  awls.       -    -     -    The  dozen  0 

1011  Brad-awls  in  beech-wood  or  hard-wood  handles.     

1012 Brad-awls,  sets  of  6  to  12,  contained  in  socket  handles  of 

horn,  hard-wood,  &c The  set  0 


10     0|  0  16 


1013  AXES.  Bench,  blocking,  broad,  falling,  hedge,  ship,  wedge,  and 

wheelers'  axes.     Handles  charged  extra       -     -     The  ll>.  0     1     0|  0     2 

1014  Falling  axes  of  American  pattern,   and  variously  handled. 

H.  and  Co.'s  make Each  0 

1015  Single-hand  axes,  similar  to  the  last  but  smaller;  used  for 

felling  small  trees,  and  for  trimming  plantations     -  Each 

1016  BABB AGE'S  (C.,  Esq.),  cutter  bars,  for  turning  metal,  with  the 

slide  rest.     (See  No.  1622.) 

1017  BAKE  WELL'S   angle   meter,   for   geological  purposes.       (See 

No.  1399.) Each  2     2     02  12 

1018 Bakewell's  Geological  Hammer.     (See  No.  1397.) 0     ; 

C 


From  I  To 
5.  d.  £  5. 
2004 

13  OJ  0  16 
1000 

0    014     0 

| 

10  0  3  10 
0701 
0  9!  0  3 
1604 


7  0  1  18 
0801 
2606 


20060 


46076 


0    0  10     0 


ADVERTISEMENTS. 


HOLTZAPFFEL  AND  CO.'S  GENERAL  CATALOGUE,  1844. 

No. 
1986 

1987 
1988 
1989 
1990 
1991 
1992 
1993 
1994 

U'95 

1996 
19.07 
1998 
1999 
2000 
2001 
2002 
2003 
2004 
2005 
2006 
2007 
2008 
2009 
2010 
2011 

2012 

2013 
2014 

TURNING  TOOLS  of  numerous  kinds  to  be  used  by  hand,  supplied  either 
in  sets  or  singly  ;  handles  clwrged  extra. 

(A.)  Turning  Tools  for  Soft  Wood. 

£    «.    d. 

070 
066 
060 
060 
0  12     0 
090 
060 
060 

0  18     0 
090 
0  18     0 
090 
066 
040 
070 
04     6 
056 
1  16     0 
060 
056 
0  12     0 
0  18     0 
056 
056 

1   10     0 
1  10     0 

Chisels     ........ 

u 

jj 

Q 

(B.)  Turning  Tools  for  Hardivood 

and  Ivory. 

1  ° 

Bevil  tools,  right  and  left    - 

fi 

Drills 

^ 

^ 

O  1 

c} 

1° 

1  o 

Q 

-  Screw  tools.     The  set  of  12  pairs  of  H. 

&  Co.'s  pitches,  Nos.  1  to  1  2 

Screw  tools.     The  set  of  12  pairs  of  H. 
of  Shallow  Threads  -     -                - 

&  Co.'s  pitches,  Nos.  1  to  12 

77;  0  sot 

Screw  tools,  Nos.  1             2             3456 
3.5.  9rf.    3s.  M.    3s.  3d.    3s.     2s.  9d.  2s.  6rf.  Tlte  pah 
Screw  tools,Nos.  7             8             9         10        11          12 
2*.  Grf.    2s.  U.    2s.4d.  2s.2d.     2s.      }s.  lOrf.  Thenaii 

Tlte  same  screw  tools  are  also  used  for  brass,  iron,  and  steel. 

Some  of  the  tools,  1995  to  2010,  are  made  thinner  than  usual^  to  le  used 
for  ivory. 

2015 Tools  for  turning  the  Chinese  balls,  which  consist  of  thin  shells, 

contained  one  within  the  other.  The  balls  are  carved  by  hand, 
with  small  and  appropriate  tools,  subsequently  to  their  having 
been  separated  from  within  one  another  in  the  lathe. 

(C.)  Turning  Tools  for  Brass,  generally  with  rectangular  edges. 

2016  Flat  tools -     -Thcsetof6    tools 

2017  Point  tools 6  

2018  Round  tools 6  

2010  Square  tools 6  

2020  Milling  tools Each 

2021 Tools  for  finishing  metal  balls.     Each  tool  consists  of  a  steel  ring, 

smaller  in  diameter  than  the  ball  to  be  turned. 

(D.)  Turning  Tools  for  Iron  and  Steel,  strong t  ivith  keen  edges. 

Flat  tools TJie  set  of  6    tr>oh 

Gravers 6 

Hook  or  heel  tools 

Round  tools »  — 

Triangular  tools C  


066 
066 
066 


0    4 
0     2 


0     5 
0     4 

0 

0 


6 
(J 

4     6 
6     6 


0     5     G 


ADVERTISEMENTS. 


APPENDIX  (A.)— TO  HOLTZAPFFEL  AND  CO.'S  GENERAL  CATALOGUE,  If 

HOLTZAPFFEL    &    CO.'S    LIST    OF    TABLE    CUTLERY. 


A  COMPLETE  LIST  OF  GENERAL  CUTLERY, 

INCLUDING  PBN,  POCKET,  SPORTSMEN'S,  AND  OTHER  KNIVES  ;  RAZORS,  SCISSORS,  AND  MISCELLANEOUS 
ARTICLES,  WILL  BE  FOUND  ON  PAGES  13  TO  16  OF  THE  GENERAL  CATALOGUE. 


SHEFFIELD-MADE  BLADES. 

No 

Table 
Knives  and 
Forks 
The  Dozen. 

Dessert 
Knives  and 
Forks 
The  Dozen. 

Carving 
Knives  and 
Forks 
The  Pair. 

£.    t.  d. 

050 
060 
080 
0    10    0 
0    12    0 
0    14    0 
0    16    0 
0    18    0 
0    0 
2    0 
4    0 
6    0 
8    0 
10    0 
13    0 
1    16    0 

200 
220 

300 

3    10    0 

£.    s.  d. 

080 
0    10    0 
0    12    0 
0    14    0 
0    16    0 
0    18    0 
1      0    0 
1      0    0 
1      2    0 
0    18    0 
1      0    0 
1      4    6 
1      6    0 

1    10    0 
1     12    0 

2    10    0 
300 

£.     S.  d. 

030 
036 
040 
046 
050 
056 
060 
066 
070 
070 
070 
076 
080 

086 
090 

0    12    0 
0    13    0 

r  l~ 

Common  strong  Knives  and  Forks,  in  Plain  Handles  of  Bone  J    2  — 
or  Wood,  either  solid  or  in  halves,  and  rivetted         .        .    .|    3— 
I  4- 
r  5- 
Plain  Shear-steel  Knives  and  Forks,  in  Handles  of  good  Bone  I    6  — 
or  Stained  Horn,  either  solid,  or  in  halves  and  rivetted    .    .  |    7  — 
I  8- 

Warranted  Knives  and  Forks,  in  solid  Handles  of  the  best  [  ^~ 
Natural  Buck  or  Stag  Horn,  also  in  Octagon  Handles  of  Ox  J  ™~ 

{13- 
14— 

16- 
LONDON  MADE  BLADES. 

In  Ivory  Octagon  Handles           17— 
In  Ivory  Octagon  Handles  of  finer  quality        .         •                        18  — 
In  fine  Transparent  African  Ivory  Octagon  Handles  with  Silver  ) 
Ferrules        J 

In  fine  Transparent  African  Ivory  Fluted  Octagon  Handles  )  9ft 
with  Silver  Ferrules           f 

SETS  OF  TABLE  CUTLERY  IN  CASES. 

The  Cases  are  of  Mahogany,  or  Oak,  and  bound  with  brass  i  they  are  lined  with  baize,  and  nave 
separate  compartments  for  each  piece. 
The  Cases  are  charged  a  little  extra  if  lined  with  cloth  or  with  cotton  velvet. 
All  the  Knives  supplied  in  these  Cases  have  balanced  handles  ,•  but  Table  Forks,  and  Dessert  Forks, 
are  not  included  in  the  annexed  Prices. 

\ 

Sets  of  2  dozen  Table  Knives,  2  dozen  Dessert  Knives,  2  Pairs  of  ) 
Table  Carvers,  and  1  Knife  Steel       .                                              .  j 
Sets  of  4  dozen  Table  Knives,  3  dozen  Dessert  Knives,  2  Pairs  of 
Table,  and  2  Pairs  of  Poultry  Carvers,  and  1  Knife  Steel         .    . 
Sets  of  6  dozen  Table  Knives,  4  dozen  Dessert  Knives,  3  Pairs 
of  Table,  and  3  Pairs  of  Poultry  Carvers,  1  Knife  Steel,  and 
1  Cheese  Scoop         
Sets  of  8  dozen  Table  Knives,  6  dozen  Dessert  Knives,  4  Pairs  ' 
of  Table  and  4  Pairs  of  Poultry^  Carvers,  2  Knife  Steels,  and 

Cutlery 
No.  18. 

No.ei& 

Cutlery- 
No.  20. 

£.  s.    d. 
9  10    0 

15  15    0 
22    0    0 

30    0    0 

£.  s.   d. 
12    5    0 

21    0    0 
*29    0    0 

40    0    0 

£.  s.  d. 
13  10    0 

23  10    0 
33    0    0 

45    0    0 

i 

DESSERT  KNIVES  AND  FORKS  OF  STEEL,  PLATED  WITH  SILVER,  AND  CONTAINED  IN  CASES. 

Sets  of  ]  dozen  pairs,  variously  mounted  in  Ivory  Handles 
Sets  of  1  dozen  pairs,  variously  mounted  in  Pearl  Handles      .         • 

£.  s.  d. 
4  10    0 
600 

£.  ,.  d. 
600 
800 

£.  s.  d. 
7  10    0 
10    0    0 

Knives  with  balanced  handles  3*.  the  dozen  extra. 

Knives  without  Forks,  one  third  less  the  dozen  than  Knives  and  Forks. 

New  blades  to  old  handles  12*.  to  18s.  the  dozen. 

A  general  assortment  of  fowl,  ham,  and  scimitar  Carving  Knives,  Forks,  and  Steels,  in  ivory,  buck, 

and  stag-horn  handles,  plain,  or  with  silver  mountings. 
Also  sets  of  Knives  for  the  kitchen,  &c.,  namely,  asparagus,  butchers',  bread,  butter,  cheese,  cooks'  and 

root  knives,  and  steels  ;  and  cutlet,  mincing,  and  steak  choppers,  with  iron,  horn,  or  wood  handles. 
Crests,  Initials,  or  Names  engraved  on  the  handles  to  order. 
Cutlery  of  every  description  repaired,  ground,  or  set,  and  made  to  any  given  pattern. 

WAREHOUSE,  64,  CHARIN<J  CROSS.]  [MANUFACTORY,  127,  LONG  ACHE. 


PLEASE  DO  NOT  REMOVE 
CARDS  OR  SLIPS  FROM  THIS  POCKET 

UNIVERSITY  OF  TORONTO  LIBRARY 


TT  Holtzapffel,   Charles 

H  ^  Turning  and  mechanical 

v. 3  manipulation 

physical  & 
Applied  Sci.